Showing 1–49 of 49 results for author: Deisting, A

Enhancing Neutrinoless Double-Beta Decay Sensitivity of Liquid-Xenon Time Projection Chamber with Augmented Convolutional Neural Network

Authors: E. Aprile, J. Aalbers, K. Abe, M. Adrover, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, S. R. Armbruster, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, R. M. Braun, G. Bruni, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez , et al. (151 additional authors not shown)

Abstract: Dual-phase time projection chamber (TPC) that employs a multi-ton-scale liquid xenon (LXe) target mass is a pioneering detector technology to search for dark matter. Beyond its advantage in dark matter direct detection efforts, the natural xenon target allows it to search for the neutrinoless double-beta decay ($0νββ$) process, which would violate lepton number conservation and indicate that neutr… ▽ More Dual-phase time projection chamber (TPC) that employs a multi-ton-scale liquid xenon (LXe) target mass is a pioneering detector technology to search for dark matter. Beyond its advantage in dark matter direct detection efforts, the natural xenon target allows it to search for the neutrinoless double-beta decay ($0νββ$) process, which would violate lepton number conservation and indicate that neutrinos are Majorana particles. However, such $0νββ$ searches have been limited by gamma-ray backgrounds originating from the detector materials. In this work, we designed an augmented convolutional neural network (A-CNN) model to extract additional event-topology information from detector data. Using simulation and calibration data from XENONnT, a leading LXe TPC experiment, our model achieved over 60% background rejection while maintaining 90% signal acceptance. This rejection power improves XENONnT's projected sensitivity of the $^{136}$Xe $0νββ$ search by about 40%. The implementation of A-CNN in the data analysis of future liquid xenon observatories, such as XLZD, will further enhance their sensitivities for $0νββ$ with $^{136}$Xe. △ Less

Submitted 20 March, 2026; originally announced March 2026.

Light Dark Matter Search with 7.8 Tonne-Year of Ionization-Only Data in XENONnT

Authors: E. Aprile, J. Aalbers, K. Abe, M. Adrover, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, S. R. Armbruster, F. Arneodo, L. Baudis, M. Bazyk, V. Beligotti, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, R. M. Braun, G. Bruni, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso , et al. (152 additional authors not shown)

Abstract: We report on a blinded search for dark matter (DM) using ionization-only (S2-only) signals in XENONnT with a total exposure of $7.83\mathrm{tonne}\times\mathrm{year}$ over 579 days in three science runs. Dedicated background suppression techniques and the first complete S2-only background model in XENONnT provide sensitivity to nuclear recoils of [0.5, 5.0] $\mathrm{keV_\mathrm{nr}}$ and electroni… ▽ More We report on a blinded search for dark matter (DM) using ionization-only (S2-only) signals in XENONnT with a total exposure of $7.83\mathrm{tonne}\times\mathrm{year}$ over 579 days in three science runs. Dedicated background suppression techniques and the first complete S2-only background model in XENONnT provide sensitivity to nuclear recoils of [0.5, 5.0] $\mathrm{keV_\mathrm{nr}}$ and electronic recoils of [0.04, 0.7] $\mathrm{keV_\mathrm{ee}}$. No significant excess over the expected background is observed, and we set 90\% confidence level upper limits on spin-independent DM--nucleon and spin-dependent DM--neutron scattering for DM masses between 3 and 8 $\mathrm{GeV}/c^2$, as well as on DM--electron scattering, axion-like particles, and dark photons, improving on previous constraints. For spin-independent DM--nucleon scattering, we exclude cross sections above $6.0\times10^{-45} $cm$^2$ at a DM mass of 5 $\mathrm{GeV}/c^2$, pushing the XENONnT sensitivity closer to the region where coherent elastic neutrino-nucleus scattering ($\text{CE}ν\text{NS}$) becomes an irreducible background. △ Less

Submitted 30 July, 2026; v1 submitted 16 January, 2026; originally announced January 2026.

Journal ref: Phys. Rev. Lett. 137, 051003 (2026)

Development & Characterization of Electrodes for large-scale Xenon Time Projection Chambers

Authors: A. Elykov, S. Vetter, V. H. S. Wu, A. Deisting, K. Eitel, R. Gumbsheimer, M. Kara, S. Lichter, S. Lindemann, T. Luce, Y. Ma, J. Müller, K. Müller, K. Ni, U. Oberlack, M. Schumann, P. Shagin, K. Valerius, M. Zhong

Abstract: Dual-phase liquid xenon time projection chambers are the core detector elements of many experiments that conduct searches for Dark Matter and rare events, as well as in neutrino and high-energy physics. As part of this detector technology, high-voltage electrodes are instrumental for the generation of observable signals and their physical interpretation. Thus, electrode design and manufacturing ha… ▽ More Dual-phase liquid xenon time projection chambers are the core detector elements of many experiments that conduct searches for Dark Matter and rare events, as well as in neutrino and high-energy physics. As part of this detector technology, high-voltage electrodes are instrumental for the generation of observable signals and their physical interpretation. Thus, electrode design and manufacturing has to fulfill stringent requirements, and their production is associated with significant engineering challenges. In this work we describe the successful development of electrodes on the 1.5 m-scale, from their design and simulation to subsequent assembly and high-voltage testing in a gaseous argon environment. The produced electrodes were recently installed as an anode and a cathode during an upgrade to the XENONnT experiment. △ Less

Submitted 14 January, 2026; v1 submitted 20 November, 2025; originally announced November 2025.

Journal ref: JINST 21 P02035 (2026)

GRANITE: High-Resolution Imaging and Electrical Qualification of Large-Area TPC Electrodes

Authors: Shumit A. Mitra, Alexander Deisting, Jan Lommler, Uwe Oberlack, Fabian Piermaier, Quirin Weitzel, Daniel Wenz

Abstract: Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for high-voltage performance of such an experiment, we have developed a scanning setup for comprehensive electrode quality assurance. The system is built around the GRANITE (Granular Robotic Assay for Novel Integrated TPC Electro… ▽ More Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for high-voltage performance of such an experiment, we have developed a scanning setup for comprehensive electrode quality assurance. The system is built around the GRANITE (Granular Robotic Assay for Novel Integrated TPC Electrodes) facility: a gantry robot on top of a $2.5\,\text{m}\times1.8\,\text{m}$ granite table, equipped with a suite of non-contact metrology devices. We developed a coaxial wire scanning head to measure and correlate localized high-voltage discharge currents in air with high-resolution surface images. We find that the identified discharge 'hotspots' are transient and show no significant correlation with static visual features. Next, we established a quantitative relationship between artificially induced abrasive surface damage on the wires and a reduction in the discharge inception voltage. This work provides a novel non-invasive tool for qualifying wires dedicated for use in electrodes for future low-background experiments. △ Less

Submitted 3 February, 2026; v1 submitted 14 November, 2025; originally announced November 2025.

Comments: 18 pages, 8 figures, submitted to JINST

Journal ref: JINST 21 P01034 (2026)

GRANITE: Mechanical Characterization and Optical Inspection of Large-Area TPC Electrodes

Authors: Alexander Deisting, Jan Lommler, Shumit A. Mitra, Uwe Oberlack, Fabian Piermaier, Quirin Weitzel, Daniel Wenz

Abstract: Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for mechanical stability and high-voltage performance of such an experiment, we have developed a scanning setup for electrode quality assurance called GRANITE: Granular Robotic Assay for Novel Integrated TPC Electrodes. GRANITE i… ▽ More Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for mechanical stability and high-voltage performance of such an experiment, we have developed a scanning setup for electrode quality assurance called GRANITE: Granular Robotic Assay for Novel Integrated TPC Electrodes. GRANITE is built around a gantry robot on top of a $2.5\,\text{m}\times1.8\,\text{m}$ granite table, equipped with a suite of non-contact metrology devices. We demonstrate the setup's capabilities in two key areas: first, using laser scanners, we characterize wire tension, and in an independent measurement wire deflection due to gravity and electrostatic forces is determined. The setup achieves a precision of $20\,μ\text{m}$ for the relative measurement of only electrostatic displacement. Furthermore, GRANITE can measure gravitational sag down to $200\,μ\text{m}$ in an absolute measurement; this precision improves to $50\,μ\text{m}$ when applying model-based corrections for systematic effects. The performance achieved exceeds the needs for the characterisation of the electrode sagging in future experiments, which typically aims to ensure a maximal sag on the order of $500\,μ\text{m}$. Second, we use GRANITE's high resolution camera to image all wires of XENON1T's cathode grid. Subsets of these images are then hand sorted and used to train an autoencoder, to reliably classify wire images as either pristine wires or images containing severe anomalous features. These anomalies appear e.g. as staining and may be potential defects. The interpretation of the classification results is complicated by the fact that most wire segments are not spotless, but show a varying amount of anomalous features. Follow-up studies are needed to identify the exact nature of such features on wires. △ Less

Submitted 3 February, 2026; v1 submitted 14 November, 2025; originally announced November 2025.

Comments: 23 pages, 10 figures, submitted to JINST

Journal ref: JINST 21 P01033 (2026)

Readout electronics for low occupancy High-Pressure Gas TPCs

Authors: N. Khan, Y. Hua, I. Xiotidis, T. Alves, E. Atkin, G. Barker, D. Barrow, A. Booth, J. Borg, A. Bross, M. F. Cicala, L. Cremonesi, A. Deisting, K. Duffy, R. Gran, P. Green, A. Habig, M. Judah, T. Junk, A. Kaboth, A. Klustová, H. LeMoine, A. D. Marino, F. Martínez López, T. Mohayai , et al. (14 additional authors not shown)

Abstract: HPgTPCs have benefits such as low energy threshold, magnetisability, and 4$π$ acceptance, making them ideal for neutrino experiments such as DUNE. We present the design of an FPGA-based solution optimised for ND-GAr, which is part of the Phase-II more capable near detector for DUNE. These electronics reduce the cost significantly compared to using collider readout electronics which are typically d… ▽ More HPgTPCs have benefits such as low energy threshold, magnetisability, and 4$π$ acceptance, making them ideal for neutrino experiments such as DUNE. We present the design of an FPGA-based solution optimised for ND-GAr, which is part of the Phase-II more capable near detector for DUNE. These electronics reduce the cost significantly compared to using collider readout electronics which are typically designed for much higher occupancy and therefore, for example, need much larger numbers of FPGAs and power per channel. We demonstrate the performance of our electronics with the TOAD at Fermilab in the US at a range of pressures and gas mixtures up to 4.5barA, reading out ~10000 channels from a multi-wire proportional chamber. The operation took place between April and July of 2024. We measure the noise characteristics of the system to be sufficiently low and we identify sources of noise that can be further mitigated in the next iteration. We also note that the cooling scheme used in the test requires improvement before full-scale deployment. Despite these necessary improvements, we show that the system can fulfil the needs of a HPgTPC for a fraction of the price of collider readout electronics. △ Less

Submitted 21 October, 2025; v1 submitted 23 July, 2025; originally announced July 2025.

Comments: 26 pages, 16 figures

WIMP Dark Matter Search using a 3.1 Tonne-Year Exposure of the XENONnT Experiment

Authors: E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, S. R. Armbruster, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad , et al. (153 additional authors not shown)

Abstract: We report on a search for weakly interacting massive particle (WIMP) dark matter (DM) via elastic DM-xenon-nucleus interactions in the XENONnT experiment. We combine datasets from the first and second science campaigns resulting in a total exposure of 3.1 tonne-years. In a blind analysis of nuclear recoil events with energies above $3.8\,\mathrm{keV_{NR}}$, we find no significant excess above back… ▽ More We report on a search for weakly interacting massive particle (WIMP) dark matter (DM) via elastic DM-xenon-nucleus interactions in the XENONnT experiment. We combine datasets from the first and second science campaigns resulting in a total exposure of 3.1 tonne-years. In a blind analysis of nuclear recoil events with energies above $3.8\,\mathrm{keV_{NR}}$, we find no significant excess above background. We set new upper limits on the spin-independent WIMP-nucleon scattering cross section for WIMP masses above $10\,\mathrm{GeV}/c^2$ with a minimum of $1.7\,\times\,10^{-47}\,\mathrm{cm^2}$ at $90\,\%$ confidence level for a WIMP mass of $30\,\mathrm{GeV}/c^2$. We achieve a best median sensitivity of $1.4\,\times\,10^{-47}\,\mathrm{cm^2}$ for a $41\,\mathrm{GeV}/c^2$ WIMP. Compared to the result from the first XENONnT science dataset, we improve our sensitivity by a factor of up to 1.8. △ Less

Submitted 16 December, 2025; v1 submitted 25 February, 2025; originally announced February 2025.

Comments: Limits are included in the submission file

Journal ref: Phys. Rev. Lett. 135, 221003 (2025)

Radon Removal in XENONnT down to the Solar Neutrino Level

Authors: E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad, J. J. Cuenca-García , et al. (147 additional authors not shown)

Abstract: The XENONnT experiment has achieved an exceptionally low $^\text{222}$Rn activity concentration within its inner 5.9$\,$tonne liquid xenon detector of (0.90$\,\pm\,$0.01$\,$stat.$\,\pm\,$0.07 sys.)$\,μ$Bq/kg, equivalent to about 430 $^\text{222}$Rn atoms per tonne of xenon. This was achieved by active online radon removal via cryogenic distillation after stringent material selection. The achieved… ▽ More The XENONnT experiment has achieved an exceptionally low $^\text{222}$Rn activity concentration within its inner 5.9$\,$tonne liquid xenon detector of (0.90$\,\pm\,$0.01$\,$stat.$\,\pm\,$0.07 sys.)$\,μ$Bq/kg, equivalent to about 430 $^\text{222}$Rn atoms per tonne of xenon. This was achieved by active online radon removal via cryogenic distillation after stringent material selection. The achieved $^\text{222}$Rn activity concentration is five times lower than that in other currently operational multi-tonne liquid xenon detectors engaged in dark matter searches. This breakthrough enables the pursuit of various rare event searches that lie beyond the confines of the standard model of particle physics, with world-leading sensitivity. The ultra-low $^\text{222}$Rn levels have diminished the radon-induced background rate in the detector to a point where it is for the first time comparable to the solar neutrino-induced background, which is poised to become the primary irreducible background in liquid xenon-based detectors. △ Less

Submitted 25 April, 2025; v1 submitted 6 February, 2025; originally announced February 2025.

Low-Energy Nuclear Recoil Calibration of XENONnT with a $^{88}$YBe Photoneutron Source

Authors: XENON Collaboration, E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad , et al. (147 additional authors not shown)

Abstract: Characterizing low-energy, keV-range nuclear recoils near the detector threshold is one of the major challenges for large direct dark matter detectors. To that end, we have successfully used a Yttrium-Beryllium photoneutron source that emits 152 keV neutrons for the calibration of the light and charge yields of the XENONnT experiment for the first time. After data selection, we accumulated 474 eve… ▽ More Characterizing low-energy, keV-range nuclear recoils near the detector threshold is one of the major challenges for large direct dark matter detectors. To that end, we have successfully used a Yttrium-Beryllium photoneutron source that emits 152 keV neutrons for the calibration of the light and charge yields of the XENONnT experiment for the first time. After data selection, we accumulated 474 events from 183 hours of exposure with this source. The expected background was $55 \pm 12$ accidental coincidence events, estimated using a dedicated 152 hour background calibration run with a Yttrium-PVC gamma-only source and data-driven modeling. From these calibrations, we extracted the light (charge) yield for liquid xenon at our field strength of 23 V/cm between 0.3 (0.7) keV$_{\rm NR}$ and 5.0 keV$_{\rm NR}$. This calibration is crucial for accurately measuring the solar $^8$B neutrino coherent elastic neutrino-nucleus scattering and searching for light dark matter particles with masses below 12 GeV/c$^2$. △ Less

Submitted 30 April, 2026; v1 submitted 11 December, 2024; originally announced December 2024.

The neutron veto of the XENONnT experiment: Results with demineralized water

Authors: XENON Collaboration, E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad , et al. (145 additional authors not shown)

Abstract: Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To mitigate this background, the XENONnT experiment is equipped with a novel gadolinium-doped water Cherenkov detector, which encloses the xenon dual-phase time projection chamber (TPC). The neutron veto (NV)… ▽ More Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To mitigate this background, the XENONnT experiment is equipped with a novel gadolinium-doped water Cherenkov detector, which encloses the xenon dual-phase time projection chamber (TPC). The neutron veto (NV) tags neutrons via their capture on gadolinium or hydrogen, which release $γ$-rays that are subsequently detected as Cherenkov light. In this work, we present the key features and the first results of the XENONnT NV when operated with demineralized water in the initial phase of the experiment. Its efficiency for detecting neutrons is $(82\pm 1)\,\%$, the highest neutron detection efficiency achieved in a water Cherenkov detector. This enables a high efficiency of $(53\pm 3)\,\%$ for the tagging of WIMP-like neutron signals, inside a tagging time window of $250\,\mathrm{μs}$ between TPC and NV, leading to a livetime loss of $1.6\,\%$ during the first science run of XENONnT. △ Less

Submitted 18 December, 2024; v1 submitted 6 December, 2024; originally announced December 2024.

Journal ref: Eur. Phys. J. C 85, 695 (2025)

Neutrinoless Double Beta Decay Sensitivity of the XLZD Rare Event Observatory

Authors: XLZD Collaboration, J. Aalbers, K. Abe, M. Adrover, S. Ahmed Maouloud, D. S. Akerib, A. K. Al Musalhi, F. Alder, L. Althueser, D. W. P. Amaral, C. S. Amarasinghe, A. Ames, B. Andrieu, N. Angelides, E. Angelino, B. Antunovic, E. Aprile, H. M. Araújo, J. E. Armstrong, M. Arthurs, M. Babicz, D. Bajpai, A. Baker, M. Balzer, J. Bang , et al. (419 additional authors not shown)

Abstract: The XLZD collaboration is developing a two-phase xenon time projection chamber with an active mass of 60 to 80 t capable of probing the remaining WIMP-nucleon interaction parameter space down to the so-called neutrino fog. In this work we show that, based on the performance of currently operating detectors using the same technology and a realistic reduction of radioactivity in detector materials,… ▽ More The XLZD collaboration is developing a two-phase xenon time projection chamber with an active mass of 60 to 80 t capable of probing the remaining WIMP-nucleon interaction parameter space down to the so-called neutrino fog. In this work we show that, based on the performance of currently operating detectors using the same technology and a realistic reduction of radioactivity in detector materials, such an experiment will also be able to competitively search for neutrinoless double beta decay in $^{136}$Xe using a natural-abundance xenon target. XLZD can reach a 3$σ$ discovery potential half-life of 5.7$\times$10$^{27}$ yr (and a 90% CL exclusion of 1.3$\times$10$^{28}$ yr) with 10 years of data taking, corresponding to a Majorana mass range of 7.3-31.3 meV (4.8-20.5 meV). XLZD will thus exclude the inverted neutrino mass ordering parameter space and will start to probe the normal ordering region for most of the nuclear matrix elements commonly considered by the community. △ Less

Submitted 30 April, 2025; v1 submitted 23 October, 2024; originally announced October 2024.

Comments: 29 pages, 7 figures

Journal ref: J. Phys. G: Nucl. Part. Phys. 52 (2025) 045102

The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics

Authors: XLZD Collaboration, J. Aalbers, K. Abe, M. Adrover, S. Ahmed Maouloud, D. S. Akerib, A. K. Al Musalhi, F. Alder, L. Althueser, D. W. P. Amaral, C. S. Amarasinghe, A. Ames, B. Andrieu, N. Angelides, E. Angelino, B. Antunovic, E. Aprile, H. M. Araújo, J. E. Armstrong, M. Arthurs, M. Babicz, A. Baker, M. Balzer, J. Bang, E. Barberio , et al. (419 additional authors not shown)

Abstract: This report describes the experimental strategy and technologies for XLZD, the next-generation xenon observatory sensitive to dark matter and neutrino physics. In the baseline design, the detector will have an active liquid xenon target of 60 tonnes, which could be increased to 80 tonnes if the market conditions for xenon are favorable. It is based on the mature liquid xenon time projection chambe… ▽ More This report describes the experimental strategy and technologies for XLZD, the next-generation xenon observatory sensitive to dark matter and neutrino physics. In the baseline design, the detector will have an active liquid xenon target of 60 tonnes, which could be increased to 80 tonnes if the market conditions for xenon are favorable. It is based on the mature liquid xenon time projection chamber technology used in current-generation experiments, LZ and XENONnT. The report discusses the baseline design and opportunities for further optimization of the individual detector components. The experiment envisaged here has the capability to explore parameter space for Weakly Interacting Massive Particle (WIMP) dark matter down to the neutrino fog, with a 3$σ$ evidence potential for WIMP-nucleon cross sections as low as $3\times10^{-49}\rm\,cm^2$ (at 40 GeV/c$^2$ WIMP mass). The observatory will also have leading sensitivity to a wide range of alternative dark matter models. It is projected to have a 3$σ$ observation potential of neutrinoless double beta decay of $^{136}$Xe at a half-life of up to $5.7\times 10^{27}$ years. Additionally, it is sensitive to astrophysical neutrinos from the sun and galactic supernovae. △ Less

Submitted 28 October, 2025; v1 submitted 22 October, 2024; originally announced October 2024.

Comments: 33 pages, 14 figures

Journal ref: Eur. Phys. J. C (2025) 85: 1192

Model-independent searches of new physics in DARWIN with a semi-supervised deep learning pipeline

Authors: J. Aalbers, K. Abe, M. Adrover, S. Ahmed Maouloud, L. Althueser, D. W. P. Amaral, B. Andrieu, E. Angelino, D. Antón Martin, B. Antunovic, E. Aprile, M. Babicz, D. Bajpai, M. Balzer, E. Barberio, L. Baudis, M. Bazyk, N. F. Bell, L. Bellagamba, R. Biondi, Y. Biondi, A. Bismark, C. Boehm, K. Boese, R. Braun , et al. (209 additional authors not shown)

Abstract: We present a novel deep learning pipeline to perform a model-independent, likelihood-free search for anomalous (i.e., non-background) events in the proposed next generation multi-ton scale liquid Xenon-based direct detection experiment, DARWIN. We train an anomaly detector comprising a variational autoencoder and a classifier on extensive, high-dimensional simulated detector response data and cons… ▽ More We present a novel deep learning pipeline to perform a model-independent, likelihood-free search for anomalous (i.e., non-background) events in the proposed next generation multi-ton scale liquid Xenon-based direct detection experiment, DARWIN. We train an anomaly detector comprising a variational autoencoder and a classifier on extensive, high-dimensional simulated detector response data and construct a one-dimensional anomaly score optimised to reject the background only hypothesis in the presence of an excess of non-background-like events. We benchmark the procedure with a sensitivity study that determines its power to reject the background-only hypothesis in the presence of an injected WIMP dark matter signal, outperforming the classical, likelihood-based background rejection test. We show that our neural networks learn relevant energy features of the events from low-level, high-dimensional detector outputs, without the need to compress this data into lower-dimensional observables, thus reducing computational effort and information loss. For the future, our approach lays the foundation for an efficient end-to-end pipeline that eliminates the need for many of the corrections and cuts that are traditionally part of the analysis chain, with the potential of achieving higher accuracy and significant reduction of analysis time. △ Less

Submitted 9 May, 2026; v1 submitted 1 October, 2024; originally announced October 2024.

Comments: 10 Figures, 3 Tables, 23 Pages (incl. references. V2 Matching published version in EPJC

XENONnT Analysis: Signal Reconstruction, Calibration and Event Selection

Authors: XENON Collaboration, E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, J. R. Angevaare, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad, J. J. Cuenca-García , et al. (143 additional authors not shown)

Abstract: The XENONnT experiment, located at the INFN Laboratori Nazionali del Gran Sasso, Italy, features a 5.9 tonne liquid xenon time projection chamber surrounded by an instrumented neutron veto, all of which is housed within a muon veto water tank. Due to extensive shielding and advanced purification to mitigate natural radioactivity, an exceptionally low background level of (15.8 $\pm$ 1.3) events/(to… ▽ More The XENONnT experiment, located at the INFN Laboratori Nazionali del Gran Sasso, Italy, features a 5.9 tonne liquid xenon time projection chamber surrounded by an instrumented neutron veto, all of which is housed within a muon veto water tank. Due to extensive shielding and advanced purification to mitigate natural radioactivity, an exceptionally low background level of (15.8 $\pm$ 1.3) events/(tonne$\cdot$year$\cdot$keV) in the (1, 30) keV region is reached in the inner part of the TPC. XENONnT is thus sensitive to a wide range of rare phenomena related to Dark Matter and Neutrino interactions, both within and beyond the Standard Model of particle physics, with a focus on the direct detection of Dark Matter in the form of weakly interacting massive particles (WIMPs). From May 2021 to December 2021, XENONnT accumulated data in rare-event search mode with a total exposure of one tonne $\cdot$ year. This paper provides a detailed description of the signal reconstruction methods, event selection procedure, and detector response calibration, as well as an overview of the detector performance in this time frame. This work establishes the foundational framework for the `blind analysis' methodology we are using when reporting XENONnT physics results. △ Less

Submitted 13 September, 2024; originally announced September 2024.

Comments: 27 pages, 23 figures

First Indication of Solar $^8$B Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT

Authors: E. Aprile, J. Aalbers, K. Abe, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. Antón Martin, F. Arneodo, L. Baudis, M. Bazyk, L. Bellagamba, R. Biondi, A. Bismark, K. Boese, A. Brown, G. Bruno, R. Budnik, C. Cai, C. Capelli, J. M. R. Cardoso, A. P. Cimental Chávez, A. P. Colijn, J. Conrad, J. J. Cuenca-García , et al. (142 additional authors not shown)

Abstract: We present the first measurement of nuclear recoils from solar $^8$B neutrinos via coherent elastic neutrino-nucleus scattering with the XENONnT dark matter experiment. The central detector of XENONnT is a low-background, two-phase time projection chamber with a 5.9 t sensitive liquid xenon target. A blind analysis with an exposure of 3.51 t$\times$yr resulted in 37 observed events above 0.5 keV,… ▽ More We present the first measurement of nuclear recoils from solar $^8$B neutrinos via coherent elastic neutrino-nucleus scattering with the XENONnT dark matter experiment. The central detector of XENONnT is a low-background, two-phase time projection chamber with a 5.9 t sensitive liquid xenon target. A blind analysis with an exposure of 3.51 t$\times$yr resulted in 37 observed events above 0.5 keV, with ($26.4^{+1.4}_{-1.3}$) events expected from backgrounds. The background-only hypothesis is rejected with a statistical significance of 2.73 $σ$. The measured $^8$B solar neutrino flux of $(4.7_{-2.3}^{+3.6})\times 10^6 \mathrm{cm}^{-2}\mathrm{s}^{-1}$ is consistent with results from the Sudbury Neutrino Observatory. The measured neutrino flux-weighted CE$ν$NS cross section on Xe of $(1.1^{+0.8}_{-0.5})\times10^{-39} \mathrm{cm}^2$ is consistent with the Standard Model prediction. This is the first direct measurement of nuclear recoils from solar neutrinos with a dark matter detector. △ Less

Submitted 23 November, 2024; v1 submitted 5 August, 2024; originally announced August 2024.

Journal ref: Phys. Rev. Lett. 133, 191002 (2024)

Cosmogenic background simulations for the DARWIN observatory at different underground locations

Authors: M. Adrover, L. Althueser, B. Andrieu, E. Angelino, J. R. Angevaare, B. Antunovic, E. Aprile, M. Babicz, D. Bajpai, E. Barberio, L. Baudis, M. Bazyk, N. Bell, L. Bellagamba, R. Biondi, Y. Biondi, A. Bismark, C. Boehm, A. Breskin, E. J. Brookes, A. Brown, G. Bruno, R. Budnik, C. Capelli, J. M. R. Cardoso , et al. (158 additional authors not shown)

Abstract: Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay ($0νββ$), and axion-like particles (ALPs). Although cosmic muons are… ▽ More Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay ($0νββ$), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We determine the production rates of unstable xenon isotopes and tritium due to muon-included neutron fluxes and muon-induced spallation. These are expected to represent the dominant contributions to cosmogenic backgrounds and thus the most relevant for site selection. △ Less

Submitted 28 June, 2023; originally announced June 2023.

First operation of an ALICE OROC operated in high pressure Ar-CO$_{2}$ and Ar-CH$_{4}$

Authors: A. Ritchie-Yates, A. Deisting, G. Barker, S. Boyd, D. Brailsford, Z. Chen-Wishart, L. Cremonesi, P. Dunne, J. Eeles, P. Hamilton, A. C. Kaboth, N. Khan, A. Klustová, J. Monroe, J. Nowak, P. Singh, A. V. Waldron, J. Walding, L. Warsame, M. O. Wascko, I. Xiotidis

Abstract: New neutrino-nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long-baseline neutrino experiments to meet their sensitivity goals. A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources planned for such experiments. A gas-filled TPC is ideal for measuring low-energy par… ▽ More New neutrino-nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long-baseline neutrino experiments to meet their sensitivity goals. A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources planned for such experiments. A gas-filled TPC is ideal for measuring low-energy particles as they travel much further in gas than solid or liquid neutrino detectors. Using a high-pressure gas increases the target density, resulting in more neutrino interactions. This paper will examine the suitability of multiwire proportional chambers (MWPCs) taken from the ALICE TPC to be used as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We tested one such MWPC at up to almost 5 bar absolute (barA) with the UK high-pressure test stand at Royal Holloway, University of London. This paper reports the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.8 bar absolute with Ar-CH$_{4}$ mixtures with a CH$_{4}$ content between 2.8% and 5.0%, and so far up to 4 bar absolute with Ar-CO$_{2}$ (90-10). We measured the charge gain of this OROC using signals induced by an $^{55}$Fe source. The largest gain achieved at 4.8 bar was $64\pm2)\cdot10^{3}$ at stable conditions with an anode wire voltage of 2990 V in Ar-CH$_{4}$ (95.9-4.1). In Ar-CO$_{2}$ a gain of $(4.2\pm0.1)\cdot10^{3}$ was observed at an anode voltage of 2975 V at 4 barA gas pressure. Based on all our gain measurements, we extrapolate that, at the 10 barA pressure necessary to fit 1 tonne of gas into the ALICE TPC volume, a gain of 5000 in Ar-CO$_{2}$ (90-10) (10000 in Ar-CH$_{4}$ with $\sim\!$ 4% CH$_{4}$ content) may be achieved with an OROC anode voltage of 4.2 V ($\sim\!$ 3.1 kV). △ Less

Submitted 15 May, 2023; originally announced May 2023.

ARIADNE+: Large scale demonstration of fast optical readout for dual-phase LArTPCs at the CERN Neutrino Platform

Authors: Adam Lowe, Pablo Amedo, Diego González-Díaz, Alexander Deisting, Krishanu Majumdar, Konstantinos Mavrokoridis, Marzio Nessi, Barney Philippou, Francesco Pietropaolo, Sudikshan Ravinthiran, Filippo Resnati, Adam Roberts, Angela Saá Hernández, Christos Touramanis, Jared Vann

Abstract: Optical readout of large scale dual-phase liquid Argon TPCs is an attractive alternative to charge readout and has been successfully demonstrated on a 2x2m active region within the CERN protoDUNE cold box. ARIADNE+ uses four Timepix3 cameras imaging the S2 light produced by 16 novel, patent pending, glass THGEMs. ARIADNE+ takes advantage of the raw Timepix3 data coming natively 3D and zero suppres… ▽ More Optical readout of large scale dual-phase liquid Argon TPCs is an attractive alternative to charge readout and has been successfully demonstrated on a 2x2m active region within the CERN protoDUNE cold box. ARIADNE+ uses four Timepix3 cameras imaging the S2 light produced by 16 novel, patent pending, glass THGEMs. ARIADNE+ takes advantage of the raw Timepix3 data coming natively 3D and zero suppressed with a 1.6ns timing resolution. Three of the four THGEM quadrants implement readout in the visible light range through wavelength shifting, with the fourth featuring a VUV light intensifier, thus removing the need for wavelength shifting altogether. Cosmic ray reconstruction and energy calibration was performed. Presented is a summary of the detector setup and experimental run, preliminary analysis of the run data and future outlook for the ARIADNE program. △ Less

Submitted 25 August, 2023; v1 submitted 6 January, 2023; originally announced January 2023.

Comments: Proceedings for NuFACT2022

Highly-parallelized simulation of a pixelated LArTPC on a GPU

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, M. Adamowski, D. Adams, M. Adinolfi, C. Adriano, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, F. Akbar, K. Allison, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, R. Alvarez, P. Amedo, J. Anderson , et al. (1282 additional authors not shown)

Abstract: The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we pr… ▽ More The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on $10^3$ pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype. △ Less

Submitted 28 February, 2023; v1 submitted 19 December, 2022; originally announced December 2022.

Comments: 26 pages, 15 figures

Report number: FERMILAB-PUB-22-926-LBNF

Journal ref: JINST 2023 18 P04034

Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, M. Adamowski, D. Adams, M. Adinolfi, C. Adriano, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, F. Akbar, K. Allison, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, R. Alvarez, P. Amedo, J. Anderson , et al. (1235 additional authors not shown)

Abstract: Measurements of electrons from $ν_e$ interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is… ▽ More Measurements of electrons from $ν_e$ interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectrum is derived and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50~MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons. △ Less

Submitted 31 May, 2023; v1 submitted 2 November, 2022; originally announced November 2022.

Comments: 19 pages, 10 figures

Report number: FERMILAB-PUB-22-784, CERN-EP-DRAFT-MISC-2022-008

Journal ref: Phys. Rev. D 107, 092012 (2023)

Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, M. Adamowski, D. Adams, M. Adinolfi, C. Adriano, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, F. Akbar, B. Ali-Mohammadzadeh, K. Allison, S. Alonso Monsalve, M. AlRashed, C. Alt, A. Alton, R. Alvarez, P. Amedo , et al. (1203 additional authors not shown)

Abstract: The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a char… ▽ More The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/$c$ charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$\pm0.6$% and 84.1$\pm0.6$%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation. △ Less

Submitted 17 July, 2023; v1 submitted 29 June, 2022; originally announced June 2022.

Comments: 39 pages, 20 figures. Accepted version. Published version available in Eur. Phys. J. C 83, 618 (2023) https://doi.org/10.1140/epjc/s10052-023-11733-2

Report number: FERMILAB-PUB-22-488-AD-ESH-LBNF-ND-SCD, CERN-EP-DRAFT-MISC-2022-007

Journal ref: Eur. Phys. J. C 83, 618 (2023)

Contextual Isotope Ranking Criteria for Peak Identification in Gamma Spectroscopy Using a Large Database

Authors: Alexis Aguilar-Arevalo, Xavier Bertou, Carles Canet, Miguel A. Cruz-Pérez, Alexander Deisting, Adriana Dias, Juan Carlos D'Olivo, J. Francisco Favela-Pérez, Estela A. Garcés, Adiv González Muñoz, Jaime Octavio Guerra-Pulido, Javier Mancera-Alejandrez, Daniel José Marín-Lámbarri, Mauricio Martínez-Montero, Jocelyn Monroe, Sean Paling, Simon Peeters, Paul R. Scovell, Cenk Türkoglu, Eric Vázquez-Jáuregui, Joseph Walding

Abstract: Isotope identification is a recurrent problem in gamma spectroscopy with high purity germanium detectors. In this work, new strategies are introduced to facilitate this type of analysis. Five criteria are used to identify the parent isotopes making a query on a large database of gamma-lines from a multitude of isotopes producing an output list whose entries are sorted so that the gamma-lines with… ▽ More Isotope identification is a recurrent problem in gamma spectroscopy with high purity germanium detectors. In this work, new strategies are introduced to facilitate this type of analysis. Five criteria are used to identify the parent isotopes making a query on a large database of gamma-lines from a multitude of isotopes producing an output list whose entries are sorted so that the gamma-lines with the highest chance of being present in a sample are placed at the top. A metric to evaluate the performance of the different criteria is introduced and used to compare them. Two of the criteria are found to be superior than the others: one based on fuzzy logic, and another that makes use of the gamma relative emission probabilities. A program called histoGe implements these criteria using a SQLite database containing the gamma-lines of isotopes which was parsed from WWW Table of Radioactive Isotopes. histoGe is Free Software and is provided along with the database so they can be used to analyze spectra obtained with generic gamma-ray detectors. △ Less

Submitted 22 June, 2022; originally announced June 2022.

Comments: 12 pages, 7 tables, 7 figures

Journal ref: IEEE Transactions on Nuclear Science, 2022

Volume reduction of water samples to increase sensitivity for radioassay of lead contamination

Authors: A. Aguilar-Arevalo, C. Canet, M. A. Cruz-Pérez, A. Deisting, A. Dias, J. C. D'Olivo, F. Favela-Pérez, E. A. Garcés, A. González Muñoz, J. O. Guerra-Pulido, J. Mancera-Alejandrez, D. J. Marín-Lámbarri, M. Martinez Montero, J. R. Monroe, S. Paling, S. J. M. Peeters, P. R. Scovell, C. Türkoğlu, E. Vázquez-Jáuregui, J. Walding

Abstract: The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To increase the sensitivity of low cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 ($^{210}Pb$), as a means to increase t… ▽ More The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To increase the sensitivity of low cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 ($^{210}Pb$), as a means to increase the solute's concentration. $^{210}$Pb is a radioactive lead isotope and its concentration in a water sample can be measured with e.g. High Purity Germanium (HPGe) detectors at the Boulby Underground Germanium Suite. Concentrations close to the WHO limit have not been examined. This paper presents a measurement of the volume reduction technique retaining $99\pm(9)\%$ of $^{210}$Pb starting from a concentration of $1.9\times10^{-6}$ ppb before reduction and resulting in $2.63\times10^{-4}$ ppb after reduction. This work also applies the volume reduction technique to London tap water and reports the radioassay results from gamma counting in HPGe detectors. Among other radio-isotopes, $^{40}$K, $^{210}$Pb, $^{131}$I and $^{177}$Lu were identified at measured concentrations of $2.83\times10^{3}$ ppb, $2.55\times10^{-7}$ ppb, $5.06\times10^{-10}$ ppb and $5.84\times10^{-10}$ ppb in the London tap water sample. This technique retained $90\pm50\%$ of $^{40}$K. Stable lead was inferred from the same water sample at a measured concentration of 0.012 ppb, prior to reduction. △ Less

Submitted 9 May, 2022; originally announced May 2022.

Separation of track- and shower-like energy deposits in ProtoDUNE-SP using a convolutional neural network

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, M. Adamowski, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. AlRashed, C. Alt, A. Alton, R. Alvarez, P. Amedo, J. Anderson , et al. (1204 additional authors not shown)

Abstract: Liquid argon time projection chamber detector technology provides high spatial and calorimetric resolutions on the charged particles traversing liquid argon. As a result, the technology has been used in a number of recent neutrino experiments, and is the technology of choice for the Deep Underground Neutrino Experiment (DUNE). In order to perform high precision measurements of neutrinos in the det… ▽ More Liquid argon time projection chamber detector technology provides high spatial and calorimetric resolutions on the charged particles traversing liquid argon. As a result, the technology has been used in a number of recent neutrino experiments, and is the technology of choice for the Deep Underground Neutrino Experiment (DUNE). In order to perform high precision measurements of neutrinos in the detector, final state particles need to be effectively identified, and their energy accurately reconstructed. This article proposes an algorithm based on a convolutional neural network to perform the classification of energy deposits and reconstructed particles as track-like or arising from electromagnetic cascades. Results from testing the algorithm on data from ProtoDUNE-SP, a prototype of the DUNE far detector, are presented. The network identifies track- and shower-like particles, as well as Michel electrons, with high efficiency. The performance of the algorithm is consistent between data and simulation. △ Less

Submitted 30 June, 2022; v1 submitted 31 March, 2022; originally announced March 2022.

Comments: 31 pages, 15 figures

Report number: FERMILAB-PUB-22-240-AD-ESH-LBNF-ND-SCD, CERN-EP-2022-077

Journal ref: Eur.Phys.J.C 82 (2022) 10, 903

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, M. Adamowski, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. AlRashed, C. Alt, A. Alton, R. Alvarez, P. Amedo, J. Anderson , et al. (1202 additional authors not shown)

Abstract: DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6x6x6m3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and… ▽ More DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6x6x6m3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties △ Less

Submitted 3 June, 2022; v1 submitted 30 March, 2022; originally announced March 2022.

Comments: 31 pages, 29 figures

Report number: CERN-EP-DRAFT-MISC-2022-003; FERMILAB-PUB-22-242-LBNF

PlomBOX -- development of a low-cost CMOS device for environmental monitoring

Authors: A. Aguilar-Arevalo, E. Alba Posse, M. Alvarez, H. Arnaldi, H. Asorey, X. Bertou, A. Colque, A. Deisting, A. Dias, J. C. D'Olivo, F. Favela-Pérez, Y. Gándola, E. A. Garcés, J. Gasulla, M. Gómez Berisso, A. González Muñoz, J. O. Guerra-Pulido, S. Gutierrez, S. Jois, J. Lipovetzky, J. Lovera, M. B. Lovino, D. J. Marín-Lámbarri, L. Marpegan, D. Martín , et al. (14 additional authors not shown)

Abstract: This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor (£10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluor… ▽ More This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor (£10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluoresce or change colour when in the presence of lead. A genetically modified strain of Escherichia coli sensitive to lead concentrations up to 10 ppb is being developed. This constitutes the biosensor that fluoresces in proportion to the presence of lead. b) Bacteria response is imaged using a microprocessor (ESP32) with a camera module. This constitutes the optical metrology component of the PlomBOX. c) Data acquisition and control of the PlomBOX is achieved through a Bluetooth connection with the PlomApp, a custom-developed mobile phone application. Data are sent from the PlomApp to a database where a bespoke automated analysis software provides a result of the lead concentration in a sample of water. This paper reports on the instrumentation challenges of developing the electronics for the PlomBOX and on the first prototype. △ Less

Submitted 10 January, 2022; originally announced January 2022.

Commissioning of a hybrid readout TPC test set-up and gas gain simulations

Authors: Alexander Deisting

Abstract: A hybrid readout Time Projection Chamber (TPC) has a simultaneous optical- and charge readout. The optical readout provides 2D images of particle tracks in the active volume, whilst the charge readout provides additional information on the particle position perpendicular to the image plane. A hybrid readout TPC working at high pressure is an attractive device for physics cases where an excellent s… ▽ More A hybrid readout Time Projection Chamber (TPC) has a simultaneous optical- and charge readout. The optical readout provides 2D images of particle tracks in the active volume, whilst the charge readout provides additional information on the particle position perpendicular to the image plane. A hybrid readout TPC working at high pressure is an attractive device for physics cases where an excellent space point resolution and a high target density is required as e.g. measuring a neutrino beam at the source of a long baseline neutrino oscillation experiment. In this paper we present two different lines of work towards the goal of developing hybrid TPC technology: a) Commissioning of a set-up with gas electron multipliers employing optical and charge readout. b) An analytical parametrisation of the gas gain for a multi wire proportional chamber based on garfield++ simulations, which - when validated with measurements - allows to skip these simulations in the future altogether. △ Less

Submitted 7 January, 2022; originally announced January 2022.

Comments: Proceedings of TIPP 2021, submitted to: Journal of Physics: Conference Series

Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. AlRashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopoulos, M. Andreotti , et al. (1132 additional authors not shown)

Abstract: The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on t… ▽ More The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 3$σ$ (5$σ$) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3$σ$ level with a 100 kt-MW-yr exposure for the maximally CP-violating values $δ_{\rm CP}} = \pmπ/2$. Additionally, the dependence of DUNE's sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest. △ Less

Submitted 3 September, 2021; originally announced September 2021.

Report number: FERMILAB-PUB-21-391-ND

Design, construction and operation of the ProtoDUNE-SP Liquid Argon TPC

Authors: DUNE Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopoulos, M. Andreotti, M. P. Andrews , et al. (1158 additional authors not shown)

Abstract: The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber (LArTPC) that was constructed and operated in the CERN North Area at the end of the H4 beamline. This detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE), which will be constructed at the Sandford Underground Research Facility (SURF) in Lead, South Dakota, USA.… ▽ More The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber (LArTPC) that was constructed and operated in the CERN North Area at the end of the H4 beamline. This detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE), which will be constructed at the Sandford Underground Research Facility (SURF) in Lead, South Dakota, USA. The ProtoDUNE-SP detector incorporates full-size components as designed for DUNE and has an active volume of $7\times 6\times 7.2$~m$^3$. The H4 beam delivers incident particles with well-measured momenta and high-purity particle identification. ProtoDUNE-SP's successful operation between 2018 and 2020 demonstrates the effectiveness of the single-phase far detector design. This paper describes the design, construction, assembly and operation of the detector components. △ Less

Submitted 23 September, 2021; v1 submitted 4 August, 2021; originally announced August 2021.

Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report

Authors: A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, G. Adamov, D. Adams, M. Adinolfi, A. Aduszkiewicz, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, N. Anfimov, A. Ankowski, M. Antonova, S. Antusch , et al. (1041 additional authors not shown)

Abstract: This report describes the conceptual design of the DUNE near detector This report describes the conceptual design of the DUNE near detector △ Less

Submitted 25 March, 2021; originally announced March 2021.

Comments: 314 pages, 185 figures

Report number: FERMILAB-PUB-21-067-E-LBNF-PPD-SCD-T

A High Pressure Time Projection Chamber with Optical Readout

Authors: Alexander Deisting, Abigail Victoria Waldron, Edward Atkin, Gary Barker, Anastasia Basharina-Freshville, Christopher Betancourt, Steven Boyd, Dominic Brailsford, Zachary Chen-Wishart, Linda Cremonesi, Adriana Dias, Patrick Dunne, Jennifer Haigh, Philip Hamacher-Baumann, Sebastian Jones, Asher Kaboth, Alexander Korzenev, William Ma, Philippe Mermod, Maria Mironova, Jocelyn Monroe, Ryan Nichol, Toby Nonnenmacher, Jaroslaw Nowak, William Parker , et al. (11 additional authors not shown)

Abstract: Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these… ▽ More Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPTPC with an argon based gas mixture. We report on the successful hybrid charge and optical readout, using four CCD cameras, of signals from Am-241 sources. △ Less

Submitted 2 June, 2021; v1 submitted 12 February, 2021; originally announced February 2021.

Comments: 40 pages, 24 figures

The upgrade of the ALICE TPC with GEMs and continuous readout

Authors: J. Adolfsson, M. Ahmed, S. Aiola, J. Alme, T. Alt, W. Amend, F. Anastasopoulos, C. Andrei, M. Angelsmark, V. Anguelov, A. Anjam, H. Appelshäuser, V. Aprodu, O. Arnold, M. Arslandok, D. Baitinger, M. Ball, G. G. Barnaföldi, E. Bartsch, P. Becht, R. Bellwied, A. Berdnikova, M. Berger, N. Bialas, P. Bialas , et al. (210 additional authors not shown)

Abstract: The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous re… ▽ More The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020. △ Less

Submitted 25 March, 2021; v1 submitted 17 December, 2020; originally announced December 2020.

Comments: 88 pages, 60 figures

Journal ref: JINST 16 (2021) P03022

Characterization of Germanium Detectors for the First Underground Laboratory in Mexico

Authors: A. Aguilar-Arevalo, S. Alvarado-Mijangos, X. Bertou, C. Canet, M. A. Cruz-Pérez, A. Deisting, A. Dias, J. C. D'Olivo, F. Favela-Pérez, E. A. Garcés, A. González Muñoz, J. O. Guerra-Pulido, J. Mancera-Alejandrez, D. J. Marín-Lámbarri, M. Martínez Montero, J. Monroe, C. Iván Ortega-Hernández, S. Paling, S. Peeters, D. Ruíz Esparza Rodríguez, P. R. Scovell, C. Türkoğlu, E. Vázquez-Jáuregui, J. Walding

Abstract: This article reports the characterization of two High Purity Germanium detectors performed by extracting and comparing their efficiencies using experimental data and Monte Carlo simulations. The efficiencies were calculated for pointlike $γ$-ray sources as well as for extended calibration sources. Characteristics of the detectors such as energy linearity, energy resolution, and full energy peak ef… ▽ More This article reports the characterization of two High Purity Germanium detectors performed by extracting and comparing their efficiencies using experimental data and Monte Carlo simulations. The efficiencies were calculated for pointlike $γ$-ray sources as well as for extended calibration sources. Characteristics of the detectors such as energy linearity, energy resolution, and full energy peak efficiencies are reported from measurements performed on surface laboratories. The detectors will be deployed in a $γ$-ray assay facility that will be located in the first underground laboratory in Mexico, Laboratorio Subterráneo de Mineral del Chico (LABChico), in the Comarca Minera UNESCO Global Geopark △ Less

Submitted 24 September, 2020; originally announced September 2020.

Comments: 18 pages, 13 figures

Dosimetry and calorimetry performance of a scientific CMOS camera for environmental monitoring

Authors: Alexis Aguilar-Arevalo, Xavier Bertou, Carles Canet, Miguel Angel Cruz-Perez, Alexander Deisting, Adriana Dias, Juan Carlos D'Olivo, Francisco Favela-Perez, Estela A. Garces, Adiv Gonzalez Munoz, Jaime Octavio Guerra-Pulido, Javier Mancera-Alejandrez, Daniel Jose Marin-Lambarri, Mauricio Martinez Montero, Jocelyn Monroe, Sean Paling, Simon J. M. Peeters, Paul Scovell, Cenk Turkoglu, Eric Vazquez-Jauregui, Joseph Walding

Abstract: This paper explores the prospect of CMOS devices to assay lead in drinking water, using calorimetry. Lead occurs together with traces of radioisotopes, e.g. Lead-210, producing $γ$-emissions with energies ranging from 10 keV to several 100 keV when they decay; this range is detectable in silicon sensors. In this paper we test a CMOS camera (Oxford Instruments Neo 5.5) for its general performance a… ▽ More This paper explores the prospect of CMOS devices to assay lead in drinking water, using calorimetry. Lead occurs together with traces of radioisotopes, e.g. Lead-210, producing $γ$-emissions with energies ranging from 10 keV to several 100 keV when they decay; this range is detectable in silicon sensors. In this paper we test a CMOS camera (Oxford Instruments Neo 5.5) for its general performance as a detector of x-rays and low energy $γ$-rays and assess its sensitivity relative to the World Health Organization upper limit on lead in drinking water. Energies from 6 keV to 60 keV are examined. The CMOS camera has a linear energy response over this range and its energy resolution is for the most part slightly better than 2 %. The Neo sCMOS is not sensitive to x-rays with energies below $\sim\!\!10 keV$. The smallest detectable rate is 40$\pm$3 mHz, corresponding to an incident activity on the chip of 7$\pm$4 Bq. The estimation of the incident activity sensitivity from the detected activity relies on geometric acceptance and the measured efficiency vs. energy. We report the efficiency measurement, which is 0.08$\pm$0.02 % (0.0011$\pm$0.0002 %) at 26.3 keV (59.5 keV). Taking calorimetric information into account we measure a minimal detectable rate of 4$\pm$1 mHz (1.5$\pm$0.1 mHz) for 26.3 keV (59.5 keV) $γ$-rays, which corresponds to an incident activity of 1.0$\pm$0.6 Bq (57$\pm$33 Bq). Toy Monte Carlo and Geant4 simulations agree with these results. These results show this CMOS sensor is well-suited as a $γ$- and x-ray detector with sensitivity at the few to 100 ppb level for Lead-210 in a sample. △ Less

Submitted 23 September, 2020; originally announced September 2020.

Journal ref: Sensors 2020, 20, 5746

Supernova Neutrino Burst Detection with the Deep Underground Neutrino Experiment

Authors: DUNE collaboration, B. Abi, R. Acciarri, M. A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (949 additional authors not shown)

Abstract: The Deep Underground Neutrino Experiment (DUNE), a 40-kton underground liquid argon time projection chamber experiment, will be sensitive to the electron-neutrino flavor component of the burst of neutrinos expected from the next Galactic core-collapse supernova. Such an observation will bring unique insight into the astrophysics of core collapse as well as into the properties of neutrinos. The gen… ▽ More The Deep Underground Neutrino Experiment (DUNE), a 40-kton underground liquid argon time projection chamber experiment, will be sensitive to the electron-neutrino flavor component of the burst of neutrinos expected from the next Galactic core-collapse supernova. Such an observation will bring unique insight into the astrophysics of core collapse as well as into the properties of neutrinos. The general capabilities of DUNE for neutrino detection in the relevant few- to few-tens-of-MeV neutrino energy range will be described. As an example, DUNE's ability to constrain the $ν_e$ spectral parameters of the neutrino burst will be considered. △ Less

Submitted 29 May, 2021; v1 submitted 15 August, 2020; originally announced August 2020.

Comments: 29 pages, 17 figures; paper based on DUNE Technical Design Report. arXiv admin note: substantial text overlap with arXiv:2002.03005

Report number: FERMILAB-PUB-20-380-LBNF

Off-Axis Characterisation of the CERN T10 Beam for low Momentum Proton Measurements with a High Pressure Gas Time Projection Chamber

Authors: S. B. Jones, T. S. Nonnenmacher, E. Atkin, G. J. Barker, A. Basharina-Freshville, C. Betancourt, S. B. Boyd, D. Brailsford, Z. Chen-Wishart, L. Cremonesi, A. Deisting, A. Dias, P. Dunne, J. Haigh, P. Hamacher-Baumann, A. Kaboth, A. Korzenev, W. Ma, P. Mermod, M. Mironova, J. Monroe, R. Nichol, J. Nowak, W. Parker, H. Ritchie-Yates , et al. (11 additional authors not shown)

Abstract: We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at… ▽ More We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered protons off the beam axis was used to decrease the kinetic energy of incident protons, as well as change the proton/minimum ionising particle (MIP) composition of the incident flux. Measurements of the beam properties were made using time of flight systems upstream and downstream of the TPC. The kinetic energy of protons reaching the TPC was successfully changed from $\sim0.3$ GeV without moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path length). The flux of both protons and MIPs off the beam axis was increased. The ratio of protons to MIPs vary as a function of the off-axis angle allowing for possible optimisation of the detector to select the type of required particles. Simulation informed by the time of flight measurements show that with four moderator blocks placed in the beamline, ($5.6 \pm 0.1$) protons with energies below 0.1 GeV per spill traversed the active TPC region. Measurements of the beam composition and energy are presented. △ Less

Submitted 30 July, 2020; originally announced July 2020.

Comments: 28 pages, 30 figures

Journal ref: Instruments (2020), 4, 21

First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform

Authors: DUNE Collaboration, B. Abi, A. Abed Abud, R. Acciarri, M. A. Acero, G. Adamov, M. Adamowski, D. Adams, P. Adrien, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga , et al. (970 additional authors not shown)

Abstract: The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of $7.2\times 6.0\times 6.9$ m$^3$. It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV$/c$ to 7 GeV/$c$. Beam line instrumentation provides accurate momentum measurements… ▽ More The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of $7.2\times 6.0\times 6.9$ m$^3$. It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV$/c$ to 7 GeV/$c$. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP's performance, including noise and gain measurements, $dE/dx$ calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP's successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design. △ Less

Submitted 3 June, 2021; v1 submitted 13 July, 2020; originally announced July 2020.

Comments: 93 pages, 70 figures

Report number: FERMILAB-PUB-20-059-AD-ESH-LBNF-ND-SCD, CERN-EP-2020-125

Journal ref: JINST 15 (2020) P12004

Neutrino interaction classification with a convolutional neural network in the DUNE far detector

Authors: DUNE Collaboration, B. Abi, R. Acciarri, M. A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (951 additional authors not shown)

Abstract: The Deep Underground Neutrino Experiment is a next-generation neutrino oscillation experiment that aims to measure $CP$-violation in the neutrino sector as part of a wider physics program. A deep learning approach based on a convolutional neural network has been developed to provide highly efficient and pure selections of electron neutrino and muon neutrino charged-current interactions. The electr… ▽ More The Deep Underground Neutrino Experiment is a next-generation neutrino oscillation experiment that aims to measure $CP$-violation in the neutrino sector as part of a wider physics program. A deep learning approach based on a convolutional neural network has been developed to provide highly efficient and pure selections of electron neutrino and muon neutrino charged-current interactions. The electron neutrino (antineutrino) selection efficiency peaks at 90% (94%) and exceeds 85% (90%) for reconstructed neutrino energies between 2-5 GeV. The muon neutrino (antineutrino) event selection is found to have a maximum efficiency of 96% (97%) and exceeds 90% (95%) efficiency for reconstructed neutrino energies above 2 GeV. When considering all electron neutrino and antineutrino interactions as signal, a selection purity of 90% is achieved. These event selections are critical to maximize the sensitivity of the experiment to $CP$-violating effects. △ Less

Submitted 10 November, 2020; v1 submitted 26 June, 2020; originally announced June 2020.

Comments: 39 pages, 11 figures

Journal ref: Phys. Rev. D 102, 092003 (2020)

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume IV: Far Detector Single-phase Technology

Authors: B. Abi, R. Acciarri, Mario A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, J. Anthony, M. Antonova, S. Antusch, A. Aranda Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (941 additional authors not shown)

Abstract: The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-clas… ▽ More The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. Central to achieving DUNE's physics program is a far detector that combines the many tens-of-kiloton fiducial mass necessary for rare event searches with sub-centimeter spatial resolution in its ability to image those events, allowing identification of the physics signatures among the numerous backgrounds. In the single-phase liquid argon time-projection chamber (LArTPC) technology, ionization charges drift horizontally in the liquid argon under the influence of an electric field towards a vertical anode, where they are read out with fine granularity. A photon detection system supplements the TPC, directly enhancing physics capabilities for all three DUNE physics drivers and opening up prospects for further physics explorations. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume IV presents an overview of the basic operating principles of a single-phase LArTPC, followed by a description of the DUNE implementation. Each of the subsystems is described in detail, connecting the high-level design requirements and decisions to the overriding physics goals of DUNE. △ Less

Submitted 8 September, 2020; v1 submitted 7 February, 2020; originally announced February 2020.

Comments: Minor corrections made for JINST submission, 673 pages, 312 figures (corrected errors in author list)

Report number: FERMILAB-PUB-20-027-ND

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume III: DUNE Far Detector Technical Coordination

Authors: B. Abi, R. Acciarri, Mario A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, J. Anthony, M. Antonova, S. Antusch, A. Aranda Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (941 additional authors not shown)

Abstract: The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Exper… ▽ More The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module. △ Less

Submitted 8 September, 2020; v1 submitted 7 February, 2020; originally announced February 2020.

Comments: Minor corrections made for JINST submission, 209 pages, 55 figures (updated typos in Table A.5; corrected errors in author list)

Report number: FERMILAB-PUB-20-026-ND

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics

Authors: B. Abi, R. Acciarri, Mario A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, J. Anthony, M. Antonova, S. Antusch, A. Aranda Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (941 additional authors not shown)

Abstract: The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-clas… ▽ More The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume II of this TDR, DUNE Physics, describes the array of identified scientific opportunities and key goals. Crucially, we also report our best current understanding of the capability of DUNE to realize these goals, along with the detailed arguments and investigations on which this understanding is based. This TDR volume documents the scientific basis underlying the conception and design of the LBNF/DUNE experimental configurations. As a result, the description of DUNE's experimental capabilities constitutes the bulk of the document. Key linkages between requirements for successful execution of the physics program and primary specifications of the experimental configurations are drawn and summarized. This document also serves a wider purpose as a statement on the scientific potential of DUNE as a central component within a global program of frontier theoretical and experimental particle physics research. Thus, the presentation also aims to serve as a resource for the particle physics community at large. △ Less

Submitted 25 March, 2020; v1 submitted 7 February, 2020; originally announced February 2020.

Comments: 357 pages, 165 figures (updated typos in Table 6.1 and corrected errors in author list)

Report number: FERMILAB-PUB-20-025-ND

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume I: Introduction to DUNE

Authors: B. Abi, R. Acciarri, Mario A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, J. Anthony, M. Antonova, S. Antusch, A. Aranda Fernandez, A. Ariga, L. O. Arnold, M. A. Arroyave, J. Asaadi , et al. (941 additional authors not shown)

Abstract: The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Exper… ▽ More The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology. △ Less

Submitted 8 September, 2020; v1 submitted 7 February, 2020; originally announced February 2020.

Comments: Minor corrections made for JINST submission; 244 pages, 114 figures

Report number: FERMILAB-PUB-20-024-ND

Towards a low cost lead assay technique for drinking water using CMOS sensors

Authors: Alexander Deisting

Abstract: An estimated 26 million people in low- and middle-income countries are at risk of lead exposure and there is no safe threshold for lead ingestion. Radio assay methods are not easily accessible in regions at risk, therefore a low cost and easy to use sensor is desirable. $\textrm{Pb}$ occurs together with traces of radioisotopes with decay energies in the range of $10$ to several \SI{100}{\kilo\ele… ▽ More An estimated 26 million people in low- and middle-income countries are at risk of lead exposure and there is no safe threshold for lead ingestion. Radio assay methods are not easily accessible in regions at risk, therefore a low cost and easy to use sensor is desirable. $\textrm{Pb}$ occurs together with traces of radioisotopes with decay energies in the range of $10$ to several \SI{100}{\kilo\electronvolt} and beyond. Such energies are accessible in silicon sensors. We have tested a scientific CMOS (Neo 5.5 sCMOS), optimised for optical wavelengths, as $γ$ detector for radiation in the range of $0$ to a few 10 keV. We find a minimal detectable $^{241}\textrm{Am}$ decay rate of 20 Bq for a < 1.4h measurement. Optimising our analysis software will potentially enable detecting lower rates in the same measurement time. We established that the Neo 5.5 sCMOS allows to measure a spectrum of $^{241}\textrm{Am}$ decay lines. In addition we show that it is possible to enhance the concentration of radioisotopes in water when reducing the water's volume by boiling. The knowledge gained using the scientific CMOS sensor will be transferred to commercial silicon sensors as the chips in smart phones. △ Less

Submitted 20 December, 2019; originally announced January 2020.

Comments: 2 pages, 5 figures, Submitted to the IEEE conference record

Secondary discharge studies in single and multi GEM structures

Authors: A. Deisting, C. Garabatos, P. Gasik, D. Baitinger, A. Berdnikova, M. B. Blidaru, A. Datz, F. Dufter, S. Hassan, T. Klemenz, L. Lautner, S. Masciocchi, A. Mathis, R. A. Negrao De Oliveira, A. Szabo

Abstract: Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work. Their main characteristics are the occurrence a few $10\,μ\textrm{s}$ after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directi… ▽ More Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work. Their main characteristics are the occurrence a few $10\,μ\textrm{s}$ after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directions. They can be mitigated using series resistors in the high-voltage connection to the GEM electrode facing towards an anode. The electric field at which the onset of secondary discharges occurs indeed increases with increasing resistance. Discharge propagation form GEM to GEM in a multi-GEM system affects the occurrence probability of secondary discharges in the gaps between neighbouring GEMs. Furthermore, evidence of charges flowing through the gap after the primary discharge are reported. Such currents may or may not lead to a secondary discharge. A characteristic charge, of the order of $10^{10}\,\textrm{electrons}$, has been measured as the threshold for a primary discharge to be followed by a secondary discharge, and this number slightly depends on the gas composition. A mechanism involving the heating of the cathode surface as trigger for secondary discharges is proposed. △ Less

Submitted 21 January, 2019; v1 submitted 17 January, 2019; originally announced January 2019.

Comments: 16 pages, 19 figures, 1 table, Submitted to NIM A

Journal ref: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 937, 1 September 2019, Pages 168-180

Particle identification studies with a full-size 4-GEM prototype for the ALICE TPC upgrade

Authors: M. M. Aggarwal, Z. Ahammed, S. Aiola, J. Alme, T. Alt, W. Amend, A. Andronic, V. Anguelov, H. Appelshäuser, M. Arslandok, R. Averbeck, M. Ball, G. G. Barnaföldi, E. Bartsch, R. Bellwied, G. Bencedi, M. Berger, N. Bialas, P. Bialas, L. Bianchi, S. Biswas, L. Boldizsár, L. Bratrud, P. Braun-Munzinger, M. Bregant , et al. (155 additional authors not shown)

Abstract: A large Time Projection Chamber is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019/20, the LHC will deliver Pb beams colliding at an interaction rate of about 50 kHz, which is about a factor of 50 above the present readout rate of the TPC. This will result in a significant improvement on the sensitivit… ▽ More A large Time Projection Chamber is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019/20, the LHC will deliver Pb beams colliding at an interaction rate of about 50 kHz, which is about a factor of 50 above the present readout rate of the TPC. This will result in a significant improvement on the sensitivity to rare probes that are considered key observables to characterize the QCD matter created in such collisions. In order to make full use of this luminosity, the currently used gated Multi-Wire Proportional Chambers will be replaced. The upgrade relies on continuously operated readout detectors employing Gas Electron Multiplier technology to retain the performance in terms of particle identification via the measurement of the specific energy loss by ionization d$E$/d$x$. A full-size readout chamber prototype was assembled in 2014 featuring a stack of four GEM foils as an amplification stage. The performance of the prototype was evaluated in a test beam campaign at the CERN PS. The d$E$/d$x$ resolution complies with both the performance of the currently operated MWPC-based readout chambers and the challenging requirements of the ALICE TPC upgrade program. Detailed simulations of the readout system are able to reproduce the data. △ Less

Submitted 17 June, 2018; v1 submitted 8 May, 2018; originally announced May 2018.

Comments: Submitted to NIM A

Journal ref: Nucl. Instrum. Meth. A903 (2018), 215-223

Ion mobility measurements in Ar-CO$_2$, Ne-CO$_2$, and Ne-CO$_2$-N$_{2}$ mixtures, and the effect of water contents

Authors: Alexander Deisting, Chilo Garabatos, Alexander Szabo

Abstract: A detector has been constructed for measuring ion mobilities of gas mixtures at atmospheric pressure and room temperature. The detector consists of a standard triple GEM amplification region and a drift region where ions drift. A method has been developed to measure the ions' arrival time at a cathode wire-grid by differentiating the recorded signals on this electrode. Simulations prove that this… ▽ More A detector has been constructed for measuring ion mobilities of gas mixtures at atmospheric pressure and room temperature. The detector consists of a standard triple GEM amplification region and a drift region where ions drift. A method has been developed to measure the ions' arrival time at a cathode wire-grid by differentiating the recorded signals on this electrode. Simulations prove that this method is accurate and robust. The ion mobility in different gas mixtures is measured while applying different drift field values ranging from 200 V cm$^{-1}$ to 1100 V cm$^{-1}$. From an extrapolation of a Blanc's law fit to measurements in Ar-CO$_2$ mixtures we find the reduced mobility of the drifting (cluster) ion species in pure argon to be $1.94\pm0.01$ cm$^{2}$ V$^{-1}$ s$^{-1}$ and in pure carbon-dioxide to be $1.10\pm0.01$ cm$^{2}$ V$^{-1}$ s$^{-1}$. Applying the same procedure to our measurements in Ne-CO$_2$ yields $4.06\pm0.07$ cm$^{2}$ V$^{-1}$ s$^{-1}$ and $1.09\pm0.01$ cm$^{2}$ V$^{- 1}$ s$^{-1}$ for the reduced mobilities in pure neon and carbon-dioxide, respectively. Admixtures of N$_2$ to Ne-CO$_2$ reduce somewhat the mobility. For the baseline gas mixture of the future ALICE Time Projection Chamber, Ne- CO$_2$-N$_{2}$ (90-10-5), the measured reduced mobility of the drifting ions is $2.92\pm0.04$ cm$^{2}$ V$^{-1}$ s$^{-1}$. Ion mobilities are examined for different water content ranging from 70 ppm to about 2000 ppm in the gas using Ar-CO$_2$ (90-10) and Ne-CO$_2$ (90-10). A slight decrease of ion mobility is observed for the addition of several hundred ppm of water. △ Less

Submitted 13 June, 2018; v1 submitted 26 April, 2018; originally announced April 2018.

Comments: Submitted to NIMA, 9 pages, 15 figures, 1 table

Journal ref: Nuclear Instruments and Methods in Physics Research Section A 904 (2018). pp 1-8

Discharge and stability studies for the new readout chambers of the upgraded ALICE TPC

Authors: Alexander Deisting, Chilo Garabatos

Abstract: The ALICE (A Large Ion Collider Experiment) Time Projection Chamber (TPC) at CERN LHC is presently equipped with Multi Wire Proportional Chambers (MWPCs). A gating grid prevents ions produced during the gas amplification from moving into the drift volume. The maximum drift time of the electrons together with the closure time of the gating grid allows a maximum readout rate of about 3 kHz. After th… ▽ More The ALICE (A Large Ion Collider Experiment) Time Projection Chamber (TPC) at CERN LHC is presently equipped with Multi Wire Proportional Chambers (MWPCs). A gating grid prevents ions produced during the gas amplification from moving into the drift volume. The maximum drift time of the electrons together with the closure time of the gating grid allows a maximum readout rate of about 3 kHz. After the Long Shutdown 2 (from 2021 onwards), the LHC will provide lead-lead collisions at an expected interaction rate of 50 kHz. To take data at this rate the TPC will be upgraded with new readout chambers, allowing for continuous read-out and preserving the energy and momentum resolution of the current MWPCs. Chambers with a stack of four Gas Electron Multipliers (GEMs) fulfil all the performance requirements, if the voltages applied to the GEMs are tuned properly. In order to ensure that these chambers are stable while being operated at the LHC, studies of the discharge behaviour were performed. We report on studies done with small prototypes equipped with one or two GEMs. Discharges were voluntarily induced by a combination of high-voltages across the GEM(s) and highly ionising particles. During these studies, the phenomenon of "secondary discharges" has been observed. These occur only after an initial discharge when the electric field above or below the GEM is high enough. The time between the initial and the secondary discharge ranges from several 10 us to less than 1 us, decreasing with increasing field. Using decoupling resistors in the high-voltage supply path of the bottom side of the GEM shifts the occurrence of these discharges to higher electric fields. △ Less

Submitted 19 May, 2017; v1 submitted 5 May, 2017; originally announced May 2017.

Comments: 8 pages, 9 figures

Measurements of ion mobility in argon and neon based gas mixtures

Authors: Alexander Deisting, Chilo Garabatos, Alexander Szabo, Danilo Vranic

Abstract: As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC Run$\,3$ with a substantial space charge density of positive ions in the drift volume. In order to properly simulate such space charges, knowledge of the ion mobili… ▽ More As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC Run$\,3$ with a substantial space charge density of positive ions in the drift volume. In order to properly simulate such space charges, knowledge of the ion mobility $K$ is necessary. To this end, a small gaseous detector was constructed and the ion mobility of various gas mixtures was measured. To validate the corresponding signal analysis, simulations were performed. Results are shown for several argon and neon based mixtures with different $\textrm{CO}_2$ fractions. A decrease of $K$ was measured for increasing water content. △ Less

Submitted 26 May, 2016; v1 submitted 24 March, 2016; originally announced March 2016.

Comments: 3 pages, 2 figures

Status of the R&D activities for the upgrade of the ALICE TPC

Authors: Alexander Deisting

Abstract: After the Long Shutdown 2 the LHC will provide lead-lead collisions at interaction rates as high as 50kz. In order to cope with such conditions the ALICE Time Projection Chamber (TPC) needs to be upgraded. After the upgrade the TPC will run in a continuous mode, without any degradation of the momentum and dE/dx resolution compared to the performance of the present TPC. Since readout by multi-wire… ▽ More After the Long Shutdown 2 the LHC will provide lead-lead collisions at interaction rates as high as 50kz. In order to cope with such conditions the ALICE Time Projection Chamber (TPC) needs to be upgraded. After the upgrade the TPC will run in a continuous mode, without any degradation of the momentum and dE/dx resolution compared to the performance of the present TPC. Since readout by multi-wire proportional chambers is no longer feasible with these requirements, new technologies have to be employed. In the new readout chambers the electron amplification is provided by a stack of four Gas Electron Multiplier (GEM) foils. Their high voltage settings and orientation have been optimised to provide an energy resolution better then 12% at the photopeak of 55Fe. At the same settings the Ion BackFlow into the drift volume is less than 1% of the effective number of ions produced during gas amplification and the primary ionisations. This is necessary to prevent the accumulation of space charge, which eventually will distort the field in the drift volume. To ensure stable operation at the high loads during LHC run 3 the chambers have to be robust against discharges, too. With the selected configuration in a quadruple GEM stack the discharge probability is kept at the level of $10^{-12}$ discharges per incoming hadron. An overview of the ALICE TPC upgrade activities will be given in these proceedings and the optimised settings foreseen for the GEM stacks of the future readout chambers are introduced. Furthermore the outcome of two beam time campaigns at SPS and PS (at CERN) in the end of 2014 is shown. At this campaigns the stability against discharges and the dE/dx performance of a full size readout chamber prototype was tested. In addition it is reported on charging-up studies of 4GEM stacks and on tests of electromagnetic sagging of large GEM foils. △ Less

Submitted 9 February, 2016; v1 submitted 10 January, 2016; originally announced January 2016.

Comments: 4 pages, 3 figures, Proceedings of "4th Conference on Micro-Pattern Gaseous Detectors"