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Unusual upper critical field in UTe2 revealed by magnetotransport measurements up to 42 T
Authors:
Macha Méplan,
Ilya Sheikin,
Pierre Pugnat,
Romain Barbier,
François Debray,
Cédric Grandclément,
Steffen Krämer,
Yuriy Krupko,
Frédéric Molinié,
Kévin Paillot,
Robert Pankow,
Rolf Pfister,
Luc Ronayette,
Benjamin Vincent,
Charles Simon,
Midori Amano Patino,
Gérard Lapertot,
Georg Knebel,
Dai Aoki
Abstract:
The heavy-fermion superconductor UTe2 is unique in that, at ambient pressure, it exhibits three distinct superconducting phases, two of which are induced by magnetic field. When the field is applied along the crystallographic b axis in the orthorhombic structure, the field-induced phase SC2 develops above approximately 20 T and persists up to the metamagnetic transition at Hm about 34 T. When the…
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The heavy-fermion superconductor UTe2 is unique in that, at ambient pressure, it exhibits three distinct superconducting phases, two of which are induced by magnetic field. When the field is applied along the crystallographic b axis in the orthorhombic structure, the field-induced phase SC2 develops above approximately 20 T and persists up to the metamagnetic transition at Hm about 34 T. When the magnetic field is tilted towards the c axis, another superconducting phase, SC3, emerges at very high fields above about 40 T over a certain angular range. The origin of this exotic phase remains under debate. One of the key open questions regarding the origin of SC3 is whether it is confined to the spin-polarized state above Hm, or whether it already develops at lower fields. Here, we report magnetoresistance measurements performed on a high-quality single crystal of UTe2 in static magnetic fields up to 42 T applied in the (bc) plane at temperatures down to 0.35 K. At this temperature, we find that the SC3 phase first appears at an angle of 20 deg from the b axis. At larger angles, the onset of the SC3 phase, defined by a maximum in resistivity, occurs below Hm. However, zero resistivity is reached only above Hm throughout the entire angular range investigated. These results are summarized in the resulting field-angle phase diagram. Furthermore, we find that at 21 deg the SC3 phase is rapidly suppressed with increasing temperature, whereas at 24 deg it becomes considerably more robust and persists up to about 1 K. Finally, we observe Shubnikov de Haas (SdH) oscillations in the vicinity of the c axis. The observed oscillation frequencies are in good agreement with our previous results. The field dependence of the strongest SdH frequency and of the effective mass is discussed.
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Submitted 27 June, 2026;
originally announced June 2026.
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Euclid. Properties and performance of the NISP signal estimator
Authors:
Euclid Collaboration,
F. Cogato,
B. Kubik,
R. Barbier,
S. Conseil,
E. Medinaceli,
Y. Copin,
E. Franceschi,
L. Valenziano,
N. Aghanim,
B. Altieri,
S. Andreon,
N. Auricchio,
C. Baccigalupi,
M. Baldi,
A. Balestra,
S. Bardelli,
P. Battaglia,
A. Biviano,
E. Branchini,
M. Brescia,
J. Brinchmann,
S. Camera,
G. Cañas-Herrera,
V. Capobianco
, et al. (270 additional authors not shown)
Abstract:
The Euclid spacecraft, located at the second Lagrangian point of the Sun-Earth system, hosts the Near-Infrared Spectrometer and Photometer (NISP) instrument. NISP is equipped with a mosaic of 16 HgCdTe-based detectors to acquire near-infrared photometric and spectroscopic data. To meet the spacecraft's constraints on computational resources and telemetry bandwidth, the near-infrared signal is proc…
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The Euclid spacecraft, located at the second Lagrangian point of the Sun-Earth system, hosts the Near-Infrared Spectrometer and Photometer (NISP) instrument. NISP is equipped with a mosaic of 16 HgCdTe-based detectors to acquire near-infrared photometric and spectroscopic data. To meet the spacecraft's constraints on computational resources and telemetry bandwidth, the near-infrared signal is processed onboard via a dedicated hardware-software architecture designed to fulfil the stringent Euclid's data-quality requirements. A custom application software, running on the two NISP data processing units, implements the NISP signal estimator: an ad-hoc algorithm which delivers accurate flux measurements and simultaneously estimates the quality of signal estimation through the quality factor parameter. This paper investigates the properties of the NISP signal estimator by evaluating its performance during the early flight operations of the NISP instrument. First, we revisit the assumptions on which the inference of the near-infrared signal is based and investigate the origin of the main systematics of the signal estimator through Monte Carlo simulations. Then, we test the flight performance of the NISP signal estimator. Results indicate a systematic bias lower than 0.01 e/s for 99% of the NISP pixel array, well within the noise budget of the estimated signal. We also derive an analytical expression for the variance of the NISP signal estimator, demonstrating its validity, particularly when the covariance matrix is not pre-computed. Finally, we provide a robust statistical framework to interpret the QF parameter, analyse its dependence on the signal estimator bias, and show its sensitivity to cosmic ray hits on NISP detectors. Our findings corroborate previous results on the NISP signal estimator and suggest a leading-order correction based on the agreement between flight data and simulations.
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Submitted 3 February, 2026;
originally announced February 2026.
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Euclid preparation. Overview of Euclid infrared detector performance from ground tests
Authors:
Euclid Collaboration,
B. Kubik,
R. Barbier,
J. Clemens,
S. Ferriol,
A. Secroun,
G. Smadja,
W. Gillard,
N. Fourmanoit,
A. Ealet,
S. Conseil,
J. Zoubian,
R. Kohley,
J. -C. Salvignol,
L. Conversi,
T. Maciaszek,
H. Cho,
W. Holmes,
M. Seiffert,
A. Waczynski,
S. Wachter,
K. Jahnke,
F. Grupp,
C. Bonoli,
L. Corcione
, et al. (319 additional authors not shown)
Abstract:
The paper describes the objectives, design and findings of the pre-launch ground characterisation campaigns of the Euclid infrared detectors. The pixel properties, including baseline, bad pixels, quantum efficiency, inter pixel capacitance, quantum efficiency, dark current, readout noise, conversion gain, response nonlinearity, and image persistence were measured and characterised for each pixel.…
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The paper describes the objectives, design and findings of the pre-launch ground characterisation campaigns of the Euclid infrared detectors. The pixel properties, including baseline, bad pixels, quantum efficiency, inter pixel capacitance, quantum efficiency, dark current, readout noise, conversion gain, response nonlinearity, and image persistence were measured and characterised for each pixel. We describe in detail the test flow definition that allows us to derive the pixel properties and we present the data acquisition and data quality check software implemented for this purpose. We also outline the measurement protocols of all the pixel properties presented and we provide a comprehensive overview of the performance of the Euclid infrared detectors as derived after tuning the operating parameters of the detectors. The main conclusion of this work is that the performance of the infrared detectors Euclid meets the requirements. Pixels classified as non-functioning accounted for less than 0.2% of all science pixels. IPC coupling is minimal and crosstalk between adjacent pixels is less than 1% between adjacent pixels. 95% of the pixels show a QE greater than 80% across the entire spectral range of the Euclid mission. The conversion gain is approximately 0.52 ADU/e-, with a variation less than 1% between channels of the same detector. The reset noise is approximately equal to 23 ADU after reference pixels correction. The readout noise of a single frame is approximately 13 $e^-$ while the signal estimator noise is measured at 7 $e^-$ in photometric mode and 9 $e^-$ in spectroscopic acquisition mode. The deviation from linear response at signal levels up to 80 k$e^-$ is less than 5% for 95% of the pixels. Median persistence amplitudes are less than 0.3% of the signal, though persistence exhibits significant spatial variation and differences between detectors.
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Submitted 15 July, 2025;
originally announced July 2025.
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Euclid preparation: The NISP spectroscopy channel, on ground performance and calibration
Authors:
Euclid Collaboration,
W. Gillard,
T. Maciaszek,
E. Prieto,
F. Grupp,
A. Costille,
K. Jahnke,
J. Clemens,
S. Dusini,
M. Carle,
C. Sirignano,
E. Medinaceli,
S. Ligori,
E. Franceschi,
M. Trifoglio,
W. Bon,
R. Barbier,
S. Ferriol,
A. Secroun,
N. Auricchio,
P. Battaglia,
C. Bonoli,
L. Corcione,
F. Hormuth,
D. Le Mignant
, et al. (334 additional authors not shown)
Abstract:
ESA's Euclid cosmology mission relies on the very sensitive and accurately calibrated spectroscopy channel of the Near-Infrared Spectrometer and Photometer (NISP). With three operational grisms in two wavelength intervals, NISP provides diffraction-limited slitless spectroscopy over a field of $0.57$ deg$^2$. A blue grism $\text{BG}_\text{E}$ covers the wavelength range $926$--$1366$\,nm at a spec…
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ESA's Euclid cosmology mission relies on the very sensitive and accurately calibrated spectroscopy channel of the Near-Infrared Spectrometer and Photometer (NISP). With three operational grisms in two wavelength intervals, NISP provides diffraction-limited slitless spectroscopy over a field of $0.57$ deg$^2$. A blue grism $\text{BG}_\text{E}$ covers the wavelength range $926$--$1366$\,nm at a spectral resolution $R=440$--$900$ for a $0.5''$ diameter source with a dispersion of $1.24$ nm px$^{-1}$. Two red grisms $\text{RG}_\text{E}$ span $1206$ to $1892$\,nm at $R=550$--$740$ and a dispersion of $1.37$ nm px$^{-1}$. We describe the construction of the grisms as well as the ground testing of the flight model of the NISP instrument where these properties were established.
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Submitted 18 September, 2025; v1 submitted 9 June, 2025;
originally announced June 2025.
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Low noise flux estimate and data quality control monitoring in EUCLID-NISP cosmological survey
Authors:
B. Kubik,
R. Barbier,
P. Calabria,
A. Castera,
E. Chabanat,
F. Charlieu,
J-C. Clemens,
A. Ealet,
S. Ferriol,
W. Gillard,
T. Maciaszek,
E. Prieto,
F. Schirra,
A. Secroun,
B. Serra,
G. Smadja,
A. Tilquin,
J. Zoubianb
Abstract:
Euclid mission is designed to understand the dark sector of the universe. Precise redshift measurements are provided by H2RG detectors. We propose an unbiased method of fitting the flux with Poisson distributed and correlated data, which has an analytic solution and provides a reliable quality factor - fundamental features to ensure the goals of the mission. We compare our method to other techniqu…
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Euclid mission is designed to understand the dark sector of the universe. Precise redshift measurements are provided by H2RG detectors. We propose an unbiased method of fitting the flux with Poisson distributed and correlated data, which has an analytic solution and provides a reliable quality factor - fundamental features to ensure the goals of the mission. We compare our method to other techniques of signal estimation and illustrate the anomaly detection on the flight like detectors. Although our discussion is focused on Euclid NISP instrument, much of what is discussed will be of interest to any mission using similar near-infrared sensors
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Submitted 5 June, 2025;
originally announced June 2025.
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Impact of common modes correlations and time sampling on the total noise of a H2RG near-IR detector
Authors:
B. Kubik,
R. Barbier,
A. Castera,
E. Chabanat,
S. Ferriol,
G. Smadja
Abstract:
We present the readout noise reduction methods and the 1/f noise response of an 2Kx2K HgCdTe detector similar to the detectors that will be used in the Near Infrared Spectrometer Photometer - one of the instruments of the future ESA mission named Euclid. Various algorithms of common modes subtraction are defined and compared. We show that the readout noise can be lowered by 60% using properly the…
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We present the readout noise reduction methods and the 1/f noise response of an 2Kx2K HgCdTe detector similar to the detectors that will be used in the Near Infrared Spectrometer Photometer - one of the instruments of the future ESA mission named Euclid. Various algorithms of common modes subtraction are defined and compared. We show that the readout noise can be lowered by 60% using properly the references provided within the array. A predictive model of the 1/f noise with a given frequency power spectrum is defined and compared to data taken in a wide range of sampling frequencies. In view of this model the definition of ad-hoc readout noises for different sampling can be avoided
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Submitted 5 June, 2025;
originally announced June 2025.
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Optimization of the multiple sampling and signal extraction in non-destructive exposures
Authors:
B. Kubik,
R. Barbier,
A. Castera,
E. Chabanat,
S. Ferriol,
G. Smadja
Abstract:
We derive the full covariance matrix formulae are derived for proper treatment of correlations in signal fitting procedures, extending the results from previous publications. The straight line fits performed with these matrices demonstrate that a significantly higher signal to noise is obtained when the fluence exceeds 1 e/sec/pix in particular in long (several hundreds of seconds) spectroscopic e…
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We derive the full covariance matrix formulae are derived for proper treatment of correlations in signal fitting procedures, extending the results from previous publications. The straight line fits performed with these matrices demonstrate that a significantly higher signal to noise is obtained when the fluence exceeds 1 e/sec/pix in particular in long (several hundreds of seconds) spectroscopic exposures. The improvement arising from the covariance matrix is particularly strong for the initial intercept of the fit at t=0, a quantity which provides a useful redundancy to cross check the signal quality. We demonstrate that the mode that maximizes the signal to noise ratio in all ranges of fluxes studied in this paper is the one that uses all the frames sampled during the exposure. While at low flux there is no restriction on the organization of frames within groups for fluxes lower than 1 e/sec/pix, for fluxes exceeding this value the coadding of frames shell be avoided.
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Submitted 5 June, 2025;
originally announced June 2025.
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Performance of the image persistence model for Euclid infrared detectors
Authors:
B. Kubik,
R. Barbier,
G. Smadja,
S. Ferriol,
Y. Conseil,
Y. Copin,
W. Gillard,
S. Dusini,
K. Jahnke,
E. Prieto,
N. Auricchio,
E. Balbi,
A. Balestra,
P. Battaglia,
V. Capobianco,
R. Chary,
L. Corcione,
F. Cogato,
G. Delucchi,
E. Franceschi,
L. Gabarra,
F. Gianotti,
F. Grupp,
E. Lentini,
S. Ligori
, et al. (77 additional authors not shown)
Abstract:
Large-format infrared detectors are at the heart of major ground and space-based astronomical instruments, and the HgCdTe HxRG is the most widely used. The Near Infrared Spectrometer and Photometer (NISP) of the ESA's Euclid mission launched in July 2023 hosts 16 H2RG detectors in the focal plane. Their performance relies heavily on the effect of image persistence, which results in residual images…
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Large-format infrared detectors are at the heart of major ground and space-based astronomical instruments, and the HgCdTe HxRG is the most widely used. The Near Infrared Spectrometer and Photometer (NISP) of the ESA's Euclid mission launched in July 2023 hosts 16 H2RG detectors in the focal plane. Their performance relies heavily on the effect of image persistence, which results in residual images that can remain in the detector for a long time contaminating any subsequent observations. Deriving a precise model of image persistence is challenging due to the sensitivity of this effect to observation history going back hours or even days. Nevertheless, persistence removal is a critical part of image processing because it limits the accuracy of the derived cosmological parameters. We will present the empirical model of image persistence derived from ground characterization data, adapted to the Euclid observation sequence and compared with the data obtained during the in-orbit calibrations of the satellite.
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Submitted 3 June, 2025;
originally announced June 2025.
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Euclid. IV. The NISP Calibration Unit
Authors:
Euclid Collaboration,
F. Hormuth,
K. Jahnke,
M. Schirmer,
C. G. -Y. Lee,
T. Scott,
R. Barbier,
S. Ferriol,
W. Gillard,
F. Grupp,
R. Holmes,
W. Holmes,
B. Kubik,
J. Macias-Perez,
M. Laurent,
J. Marpaud,
M. Marton,
E. Medinaceli,
G. Morgante,
R. Toledo-Moreo,
M. Trifoglio,
Hans-Walter Rix,
A. Secroun,
M. Seiffert,
P. Stassi
, et al. (310 additional authors not shown)
Abstract:
The near-infrared calibration unit (NI-CU) on board Euclid's Near-Infrared Spectrometer and Photometer (NISP) is the first astronomical calibration lamp based on light-emitting diodes (LEDs) to be operated in space. Euclid is a mission in ESA's Cosmic Vision 2015-2025 framework, to explore the dark universe and provide a next-level characterisation of the nature of gravitation, dark matter, and da…
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The near-infrared calibration unit (NI-CU) on board Euclid's Near-Infrared Spectrometer and Photometer (NISP) is the first astronomical calibration lamp based on light-emitting diodes (LEDs) to be operated in space. Euclid is a mission in ESA's Cosmic Vision 2015-2025 framework, to explore the dark universe and provide a next-level characterisation of the nature of gravitation, dark matter, and dark energy. Calibrating photometric and spectrometric measurements of galaxies to better than 1.5% accuracy in a survey homogeneously mapping ~14000 deg^2 of extragalactic sky requires a very detailed characterisation of near-infrared (NIR) detector properties, as well their constant monitoring in flight. To cover two of the main contributions - relative pixel-to-pixel sensitivity and non-linearity characteristics - as well as support other calibration activities, NI-CU was designed to provide spatially approximately homogeneous (<12% variations) and temporally stable illumination (0.1%-0.2% over 1200s) over the NISP detector plane, with minimal power consumption and energy dissipation. NI-CU is covers the spectral range ~[900,1900] nm - at cryo-operating temperature - at 5 fixed independent wavelengths to capture wavelength-dependent behaviour of the detectors, with fluence over a dynamic range of >=100 from ~15 ph s^-1 pixel^-1 to >1500 ph s^-1 pixel^-1. For this functionality, NI-CU is based on LEDs. We describe the rationale behind the decision and design process, describe the challenges in sourcing the right LEDs, as well as the qualification process and lessons learned. We also provide a description of the completed NI-CU, its capabilities and performance as well as its limits. NI-CU has been integrated into NISP and the Euclid satellite, and since Euclid's launch in July 2023 has started supporting survey operations.
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Submitted 10 July, 2024; v1 submitted 22 May, 2024;
originally announced May 2024.
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Euclid. III. The NISP Instrument
Authors:
Euclid Collaboration,
K. Jahnke,
W. Gillard,
M. Schirmer,
A. Ealet,
T. Maciaszek,
E. Prieto,
R. Barbier,
C. Bonoli,
L. Corcione,
S. Dusini,
F. Grupp,
F. Hormuth,
S. Ligori,
L. Martin,
G. Morgante,
C. Padilla,
R. Toledo-Moreo,
M. Trifoglio,
L. Valenziano,
R. Bender,
F. J. Castander,
B. Garilli,
P. B. Lilje,
H. -W. Rix
, et al. (412 additional authors not shown)
Abstract:
The Near-Infrared Spectrometer and Photometer (NISP) on board the Euclid satellite provides multiband photometry and R>=450 slitless grism spectroscopy in the 950-2020nm wavelength range. In this reference article we illuminate the background of NISP's functional and calibration requirements, describe the instrument's integral components, and provide all its key properties. We also sketch the proc…
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The Near-Infrared Spectrometer and Photometer (NISP) on board the Euclid satellite provides multiband photometry and R>=450 slitless grism spectroscopy in the 950-2020nm wavelength range. In this reference article we illuminate the background of NISP's functional and calibration requirements, describe the instrument's integral components, and provide all its key properties. We also sketch the processes needed to understand how NISP operates and is calibrated, and its technical potentials and limitations. Links to articles providing more details and technical background are included. NISP's 16 HAWAII-2RG (H2RG) detectors with a plate scale of 0.3" pix^-1 deliver a field-of-view of 0.57deg^2. In photo mode, NISP reaches a limiting magnitude of ~24.5AB mag in three photometric exposures of about 100s exposure time, for point sources and with a signal-to-noise ratio (SNR) of 5. For spectroscopy, NISP's point-source sensitivity is a SNR = 3.5 detection of an emission line with flux ~2x10^-16erg/s/cm^2 integrated over two resolution elements of 13.4A, in 3x560s grism exposures at 1.6 mu (redshifted Ha). Our calibration includes on-ground and in-flight characterisation and monitoring of detector baseline, dark current, non-linearity, and sensitivity, to guarantee a relative photometric accuracy of better than 1.5%, and relative spectrophotometry to better than 0.7%. The wavelength calibration must be better than 5A. NISP is the state-of-the-art instrument in the NIR for all science beyond small areas available from HST and JWST - and an enormous advance due to its combination of field size and high throughput of telescope and instrument. During Euclid's 6-year survey covering 14000 deg^2 of extragalactic sky, NISP will be the backbone for determining distances of more than a billion galaxies. Its NIR data will become a rich reference imaging and spectroscopy data set for the coming decades.
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Submitted 22 May, 2024;
originally announced May 2024.
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Euclid. I. Overview of the Euclid mission
Authors:
Euclid Collaboration,
Y. Mellier,
Abdurro'uf,
J. A. Acevedo Barroso,
A. Achúcarro,
J. Adamek,
R. Adam,
G. E. Addison,
N. Aghanim,
M. Aguena,
V. Ajani,
Y. Akrami,
A. Al-Bahlawan,
A. Alavi,
I. S. Albuquerque,
G. Alestas,
G. Alguero,
A. Allaoui,
S. W. Allen,
V. Allevato,
A. V. Alonso-Tetilla,
B. Altieri,
A. Alvarez-Candal,
S. Alvi,
A. Amara
, et al. (1115 additional authors not shown)
Abstract:
The current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14…
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The current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance.
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Submitted 24 September, 2024; v1 submitted 22 May, 2024;
originally announced May 2024.
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Euclid's Near-Infrared Spectrometer and Photometer ready for flight -- review of final performance
Authors:
E. Medinaceli,
L. Valenziano,
N. Auricchio,
E. Franceschi,
F. Gianotti,
P. Battaglia,
R. Farinelli,
A. Balestra,
S. Dusini,
C. Sirignano,
E. Borsato,
L. Stanco,
A. Renzi,
A. Troja,
L. Gabarra,
S. Ligori,
V. Capobianco,
L. Corcione,
D. Bonino,
G. Sirri,
L. Patrizii,
M. Tenti,
D. Di Ferdinando,
C. Valieri,
N. Mauri
, et al. (22 additional authors not shown)
Abstract:
ESA's mission Euclid, while undertaking its final integration stage, is fully qualified. Euclid will perform an extragalactic survey ($0<z<2$) by observing in the visible and near-infrared wavelength range. To detect infrared radiation, it is equipped with the Near Infrared Spectrometer and Photometer (NISP) instrument, operating in the 0.9--2 $μ$m range. In this paper, after introducing the surve…
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ESA's mission Euclid, while undertaking its final integration stage, is fully qualified. Euclid will perform an extragalactic survey ($0<z<2$) by observing in the visible and near-infrared wavelength range. To detect infrared radiation, it is equipped with the Near Infrared Spectrometer and Photometer (NISP) instrument, operating in the 0.9--2 $μ$m range. In this paper, after introducing the survey strategy, we focus our attention on the NISP Data Processing Unit's Application Software, highlighting the experimental process to obtain the final parametrization of the on-board processing of data produced by the array of 16 Teledyne HAWAII-2RG (HgCdTe) detectors. We report results from the latest ground test campaigns with the flight configuration hardware - complete optical system (Korsh anastigmat telescope), detectors array (0.56 deg$^2$ field of view), and readout systems (16 Digital Control Units and Sidecar ASICs). The performance of the on-board processing is then presented. We also describe a major issue found during the final test phase. We show how the problem was identified and solved thanks to an intensive coordinated effort of an independent review `Tiger' team, lead by ESA, and a team of NISP experts from the Euclid Consortium. An extended PLM level campaign at ambient temperature in Liège and a dedicated test campaign conducted in Marseille on the NISP EQM model eventually confirmed the resolution of the problem. Finally, we report examples of the outstanding spectrometric (using a Blue and two Red Grisms) and photometric performance of the NISP instrument, as derived from the end-to-end payload module test campaign at FOCAL 5 -- CSL; these results include the photometric Point Spread Function (PSF) determination and the spectroscopic dispersion verification.
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Submitted 6 November, 2023;
originally announced November 2023.
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Euclid Near Infrared Spectrometer and Photometer instrument flight model presentation, performance and ground calibration results summary
Authors:
T. Maciaszek,
A. Ealet,
W. Gillard,
K. Jahnke,
R. Barbier,
E. Prieto,
W. Bon,
A. Bonnefoi,
A. Caillat,
M. Carle,
A. Costille,
F. Ducret,
C. Fabron,
B. Foulon,
J. L. Gimenez,
E. Grassi,
M. Jaquet,
D. Le Mignant,
L. Martin,
T. Pamplona,
P. Sanchez,
J. C. Clémens,
L. Caillat,
M. Niclas,
A. Secroun
, et al. (73 additional authors not shown)
Abstract:
The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments. It operates in the near-IR spectral region (950-2020nm) as a photometer and spectrometer. The instrument is composed of: a cold (135 K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly, a filter wheel mechanism, a grism wheel mechanism, a calibration unit, and a thermal…
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The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments. It operates in the near-IR spectral region (950-2020nm) as a photometer and spectrometer. The instrument is composed of: a cold (135 K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly, a filter wheel mechanism, a grism wheel mechanism, a calibration unit, and a thermal control system, a detection system based on a mosaic of 16 H2RG with their front-end readout electronic, and a warm electronic system (290 K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data.
This paper presents: the final architecture of the flight model instrument and subsystems, and the performance and the ground calibration measurement done at NISP level and at Euclid Payload Module level at operational cold temperature.
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Submitted 18 October, 2022;
originally announced October 2022.
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Euclid Near Infrared Spectro-Photometer: spatial considerations on H2RG detectors interpixel capacitance and IPC corrected conversion gain from on-ground characterization
Authors:
J. Le Graët,
A. Secroun,
R. Barbier,
W. Gillard,
JC. Clemens,
S. Conseil,
S. Escoffier,
S. Ferriol,
N. Fourmanoit,
E. Kajfasz,
S. Kermiche,
B. Kubik,
G. Smadja,
J. Zoubian
Abstract:
Euclid is a major ESA mission scheduled for launch in 2023-2024 to map the geometry of the dark Universe using two primary probes, weak gravitational lensing and galaxy clustering. \Euclid's instruments, a visible imager (VIS) and an infrared spectrometer and photometer (NISP) have both been designed and built by Euclid Consortium teams. The NISP instrument will hold a large focal plane array of 1…
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Euclid is a major ESA mission scheduled for launch in 2023-2024 to map the geometry of the dark Universe using two primary probes, weak gravitational lensing and galaxy clustering. \Euclid's instruments, a visible imager (VIS) and an infrared spectrometer and photometer (NISP) have both been designed and built by Euclid Consortium teams. The NISP instrument will hold a large focal plane array of 16 near-infrared H2RG detectors, which are key elements to the performance of the NISP, and therefore to the science return of the mission.
Euclid NISP H2RG flight detectors have been individually and thoroughly characterized at Centre de Physique des Particules de Marseille (CPPM) during a whole year with a view to producing a reference database of performance pixel maps. Analyses have been ongoing and have shown the relevance of taking into account spatial variations in deriving performance parameters. This paper will concentrate on interpixel capacitance (IPC) and conversion gain. First, per pixel IPC coefficient maps will be derived thanks to single pixel reset (SPR) measurements and a new IPC correction method will be defined and validated. Then, the paper will look into correlation effects of IPC and their impact on the derivation of per super-pixel IPC-free conversion gain maps. Eventually, several conversion gain values will be defined over clearly distinguishable regions.
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Submitted 17 November, 2023; v1 submitted 5 September, 2022;
originally announced September 2022.
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Euclid preparation. XVIII. The NISP photometric system
Authors:
Euclid Collaboration,
M. Schirmer,
K. Jahnke,
G. Seidel,
H. Aussel,
C. Bodendorf,
F. Grupp,
F. Hormuth,
S. Wachter,
P. N. Appleton,
R. Barbier,
J. Brinchmann,
J. M. Carrasco,
F. J. Castander,
J. Coupon,
F. De Paolis,
A. Franco,
K. Ganga,
P. Hudelot,
E. Jullo,
A. Lancon,
A. A. Nucita,
S. Paltani,
G. Smadja,
L. M. G. Venancio
, et al. (198 additional authors not shown)
Abstract:
Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95-2.02 $μ$m range, to a 5$σ$ point-source median depth of 24.4 AB mag. This unique photometric data set will find wide use beyond Euclid's core science. In this paper, we present accurate computations of the Euclid Y_E, J_E and H_E passbands used by the Near-Infrared Spectrometer and Photometer (NISP), and the…
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Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95-2.02 $μ$m range, to a 5$σ$ point-source median depth of 24.4 AB mag. This unique photometric data set will find wide use beyond Euclid's core science. In this paper, we present accurate computations of the Euclid Y_E, J_E and H_E passbands used by the Near-Infrared Spectrometer and Photometer (NISP), and the associated photometric system. We pay particular attention to passband variations in the field of view, accounting among others for spatially variable filter transmission, and variations of the angle of incidence on the filter substrate using optical ray tracing. The response curves' cut-on and cut-off wavelengths - and their variation in the field of view - are determined with 0.8 nm accuracy, essential for the photometric redshift accuracy required by Euclid. After computing the photometric zeropoints in the AB mag system, we present linear transformations from and to common ground-based near-infrared photometric systems, for normal stars, red and brown dwarfs, and galaxies separately. A Python tool to compute accurate magnitudes for arbitrary passbands and spectral energy distributions is provided. We discuss various factors from space weathering to material outgassing that may slowly alter Euclid's spectral response. At the absolute flux scale, the Euclid in-flight calibration program connects the NISP photometric system to Hubble Space Telescope spectrophotometric white dwarf standards; at the relative flux scale, the chromatic evolution of the response is tracked at the milli-mag level. In this way, we establish an accurate photometric system that is fully controlled throughout Euclid's lifetime.
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Submitted 31 March, 2022; v1 submitted 3 March, 2022;
originally announced March 2022.
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Autocorrelation analysis for the unbiased determination of power-law exponents in single-quantum-dot blinking
Authors:
J. Houel,
Q. T. Doan,
T. Cajgfinger,
G. Ledoux,
D. Amans,
A. Aubret,
A. Dominjon,
S. Ferriol,
R. Barbier,
M. Nasilowski,
E. Lhuillier,
B. Dubertret,
C. Dujardin,
F. Kulzer
Abstract:
We present an unbiased and robust analysis method for power-law blinking statistics in the photoluminescence of single nano-emitters, allowing us to extract both the bright- and dark-state power-law exponents from the emitters' intensity autocorrelation functions. As opposed to the widely-used threshold method, our technique therefore does not require discriminating the emission levels of bright a…
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We present an unbiased and robust analysis method for power-law blinking statistics in the photoluminescence of single nano-emitters, allowing us to extract both the bright- and dark-state power-law exponents from the emitters' intensity autocorrelation functions. As opposed to the widely-used threshold method, our technique therefore does not require discriminating the emission levels of bright and dark states in the experimental intensity timetraces. We rely on the simultaneous recording of 450 emission timetraces of single CdSe/CdS core/shell quantum dots at a frame rate of 250 Hz with single photon sensitivity. Under these conditions, our approach can determine ON and OFF power-law exponents with a precision of 3% from a comparison to numerical simulations, even for shot-noise-dominated emission signals with an average intensity below 1 photon per frame and per quantum dot. These capabilities pave the way for the unbiased, threshold-free determination of blinking power-law exponents at the micro-second timescale.
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Submitted 31 October, 2014;
originally announced October 2014.
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GATE : a simulation toolkit for PET and SPECT
Authors:
S. Jan,
G. Santin,
D. Strul,
S. Staelens,
K. Assie,
D. Autret,
S. Avner,
R. Barbier,
M. Bardies,
P. M. Bloomfield,
D. Brasse,
V. Breton,
P. Bruyndonckx,
I. Buvat,
A. F. Chatziioannou,
Y. Choi,
Y. H. Chung,
C. Comtat,
D. Donnarieix,
L. Ferrer,
S. J. Glick,
C. J. Groiselle,
D. Guez,
P. -F. Honore,
S. Kerhoas-Cavata
, et al. (28 additional authors not shown)
Abstract:
Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols, and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted…
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Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols, and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at the address http://www-lphe.epfl.ch/GATE/.
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Submitted 24 August, 2004;
originally announced August 2004.
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R-parity violating supersymmetry
Authors:
R. Barbier,
C. Berat,
M. Besancon,
M. Chemtob,
A. Deandrea,
E. Dudas,
P. Fayet,
S. Lavignac,
G. Moreau,
E. Perez,
Y. Sirois
Abstract:
Theoretical and phenomenological implications of R-parity violation in supersymmetric theories are discussed in the context of particle physics and cosmology. Fundamental aspects include the relation with continuous and discrete symmetries and the various allowed patterns of R-parity breaking. Recent developments on the generation of neutrino masses and mixings within different scenarios of R-pa…
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Theoretical and phenomenological implications of R-parity violation in supersymmetric theories are discussed in the context of particle physics and cosmology. Fundamental aspects include the relation with continuous and discrete symmetries and the various allowed patterns of R-parity breaking. Recent developments on the generation of neutrino masses and mixings within different scenarios of R-parity violation are discussed. The possible contribution of R-parity-violating Yukawa couplings in processes involving virtual supersymmetric particles and the resulting constraints are reviewed. Finally, direct production of supersymmetric particles and their decays in the presence of R-parity-violating couplings is discussed together with a survey of existing constraints from collider experiments.
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Submitted 13 July, 2005; v1 submitted 3 June, 2004;
originally announced June 2004.
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A System of Interest in Spectroscopy: The qp-Rotor System
Authors:
R. Barbier,
M. Kibler
Abstract:
A rotor system, having the symmetry afforded by the two-parameter quantum algebra Uqp(u(2)), is investigated in this communication. This system is useful in rotational spectroscopy of molecules and nuclei. In particular, it is shown to lead to a model (viz., the qp-rotor model) for describing (via an energy formula and a qp-deformation of E2 reduced transition probabilities) rotational bands of…
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A rotor system, having the symmetry afforded by the two-parameter quantum algebra Uqp(u(2)), is investigated in this communication. This system is useful in rotational spectroscopy of molecules and nuclei. In particular, it is shown to lead to a model (viz., the qp-rotor model) for describing (via an energy formula and a qp-deformation of E2 reduced transition probabilities) rotational bands of deformed and superdeformed nuclei.
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Submitted 17 November, 1999;
originally announced November 1999.
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Report of the GDR working group on the R-parity violation
Authors:
R. Barbier,
C. Berat,
M. Besancon,
P. Binetruy,
G. Bordes,
F. Brochu,
P. Bruel,
F. Charles,
C. Charlot,
M. Chemtob,
P. Coyle,
M. David,
E. Dudas,
D. Fouchez,
C. Grojean,
M. Jacquet,
S. Katsanevas,
S. Lavignac,
F. Ledroit,
R. Lopez,
A. Mirea,
G. Moreau,
C. Mulet-Marquis,
E. Nagy,
F. Naraghi
, et al. (7 additional authors not shown)
Abstract:
This report summarizes the work of the "R-parity violation group" of the French Research Network (GDR) in Supersymmetry, concerning the physics of supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron and LHC and limits on R-parity violating couplings from various processes. The report includes a discussion of the recent searches at the HERA experiment, prospects for new…
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This report summarizes the work of the "R-parity violation group" of the French Research Network (GDR) in Supersymmetry, concerning the physics of supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron and LHC and limits on R-parity violating couplings from various processes. The report includes a discussion of the recent searches at the HERA experiment, prospects for new experiments, a review of the existing limits, and also theoretically motivated alternatives to R-parity and a brief discussion on the implications of R-parity violation on the neutrino masses.
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Submitted 2 October, 1998;
originally announced October 1998.
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Application of a Two-Parameter Quantum Algebra to Rotational Spectroscopy of Nuclei
Authors:
R. Barbier,
M. Kibler
Abstract:
A two-parameter quantum algebra $U_{qp}({\rm u}_2)$ is briefly investigated in this paper. The basic ingredients of a model based on the $U_{qp}({\rm u}_2)$ symmetry, the $qp$-rotator model, are presented in detail. Some general tendencies arising from the application of this model to the description of rotational bands of various atomic nuclei are summarized.
A two-parameter quantum algebra $U_{qp}({\rm u}_2)$ is briefly investigated in this paper. The basic ingredients of a model based on the $U_{qp}({\rm u}_2)$ symmetry, the $qp$-rotator model, are presented in detail. Some general tendencies arising from the application of this model to the description of rotational bands of various atomic nuclei are summarized.
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Submitted 9 February, 1996;
originally announced February 1996.
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On the Use of Quantum Algebras in Rotation-Vibration Spectroscopy
Authors:
R. Barbier,
M. Kibler
Abstract:
A two-parameter deformation of the Lie algebra u$_2$ is used, in conjunction with the rotor system and the oscillator system, to generate a model for rotation-vibration spectroscopy of molecules and nuclei.
A two-parameter deformation of the Lie algebra u$_2$ is used, in conjunction with the rotor system and the oscillator system, to generate a model for rotation-vibration spectroscopy of molecules and nuclei.
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Submitted 13 November, 1995;
originally announced November 1995.
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An $U_{qp}(u_2)$ Rotor Model for Rotational Bands of Superdeformed Nuclei
Authors:
R. Barbier,
J. Meyer,
M. Kibler
Abstract:
A nonrigid rotor model is developed from the two-parameter quantum algebra $U_{qp}({\rm u}_2)$. [This model presents the $U_{qp}({\rm u}_2)$ symmetry and shall be referred to as the qp-rotor model.] A rotational energy formula as well as a qp-deformation of E2 reduced transition probabilities are derived. The qp-rotor model is applied (through fitting procedures) to twenty rotational bands of su…
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A nonrigid rotor model is developed from the two-parameter quantum algebra $U_{qp}({\rm u}_2)$. [This model presents the $U_{qp}({\rm u}_2)$ symmetry and shall be referred to as the qp-rotor model.] A rotational energy formula as well as a qp-deformation of E2 reduced transition probabilities are derived. The qp-rotor model is applied (through fitting procedures) to twenty rotational bands of superdeformed nuclei in the $A \sim 130$, 150 and 190 mass regions. Systematic comparisons between the qp-rotor model and the q-rotor model of Raychev, Roussev and Smirnov, on one hand, and a basic three-parameter model, on the other hand, are performed on energy spectra, on dynamical moments of inertia and on B(E2) values. The physical signification of the deformation parameters q and p is discussed.
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Submitted 25 January, 1995;
originally announced January 1995.
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An Uqp(u2) Model for Rotational Bands of Nuclei
Authors:
R. Barbier,
J. Meyer,
M. Kibler
Abstract:
A rotational model is developed from a new version of the two-parameter quantum algebra $U_{qp}({\rm u}_2)$. This model is applied to the description of some recent experimental data for the rotating superdeformed nuclei $^{192-194-196-198}{\rm Pb}$ and $^{192-194 }{\rm Hg}$. A comparison between the $U_{qp}({\rm u}_2)$ model presented here and the Raychev-Roussev-Smirnov model with…
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A rotational model is developed from a new version of the two-parameter quantum algebra $U_{qp}({\rm u}_2)$. This model is applied to the description of some recent experimental data for the rotating superdeformed nuclei $^{192-194-196-198}{\rm Pb}$ and $^{192-194 }{\rm Hg}$. A comparison between the $U_{qp}({\rm u}_2)$ model presented here and the Raychev-Roussev-Smirnov model with $U_{q }({\rm su}_2)$ symmetry shows the relevance of the introduction of a second parameter of a ``quantum algebra'' type.
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Submitted 11 July, 1994;
originally announced July 1994.