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Experimental realization of a rotating radio-frequency ion trap for precision metrology
Authors:
Sun Yool Park,
Anzhou Wang,
Kia Boon Ng,
Patricia Hector Hernandez,
Addison Hartman,
Tuan Anh Nguyen,
Rohan Kompella,
Michail Athanasakis-Kaklamanakis,
Jun Ye,
Eric A. Cornell
Abstract:
We discuss the experimental realization of the rotating radio-frequency (rrf) trap, proposed by Hasegawa and Bollinger [Phys. Rev. A 72, 043403 (2005)]. Compared to a traditional linear rf (lrf) Paul trap, the rrf trap is a closer analogy to the popular mechanical lecture demonstration for a Paul trap. In an ion trap with reslistic, non-ideal electrode geometry, the rrf trap averages over angular…
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We discuss the experimental realization of the rotating radio-frequency (rrf) trap, proposed by Hasegawa and Bollinger [Phys. Rev. A 72, 043403 (2005)]. Compared to a traditional linear rf (lrf) Paul trap, the rrf trap is a closer analogy to the popular mechanical lecture demonstration for a Paul trap. In an ion trap with reslistic, non-ideal electrode geometry, the rrf trap averages over angular variations in the effective potential. This averaging provides more uniform confinement and reduces ion loss at equal confinement strength compared with the lrf trap. This feature makes the rrf trap configuration advantageous for precision metrology application, such as electron electric dipole moment (eEDM) measurements.
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Submitted 23 July, 2026;
originally announced July 2026.
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Search for a solar-bound axion halo using the Global Network of Optical Magnetometers for Exotic physics searches
Authors:
Tatum Z. Wilson,
Derek F. Jackson Kimball,
Samer Afach,
Jiexiao Bi,
B. C. Buchler,
Dmitry Budker,
Kaleb Cervantes,
Joshua Eby,
Nataniel L. Figueroa,
Ron Folman,
Jiawei Gao,
Daniel Gavilán-Martín,
Menachem Givon,
Zoran D. Grujić,
Hong Guo,
Paul Hamilton,
M. P. Hedges,
Zhejun Huang,
Dongok Kim,
Younggeun Kim,
Sami S. Khamis,
Emmanuel Klinger,
Abaz Kryemadhi,
Nina Kukowski,
Jianjun Li
, et al. (28 additional authors not shown)
Abstract:
We report on a search for a gravitationally bound solar axion halo using data from the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), a worldwide array of magnetically shielded atomic magnetometers with sensitivity to exotic spin couplings. Motivated by recent theoretical work suggesting that self-interacting ultralight axions can be captured by the Sun's gravitationa…
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We report on a search for a gravitationally bound solar axion halo using data from the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), a worldwide array of magnetically shielded atomic magnetometers with sensitivity to exotic spin couplings. Motivated by recent theoretical work suggesting that self-interacting ultralight axions can be captured by the Sun's gravitational field and thermalize into the ground state, we develop a signal model for the pseudo-magnetic fields generated by axion-proton gradient couplings in such a halo. The analysis focuses on the fifth GNOME Science Run (69 days, 12 stations), employing a cross-correlation pipeline with time-shifted daily modulation templates to search for the global, direction-dependent, monochromatic signal expected from a solar axion halo. No statistically significant candidate signals are observed. We set 95% confidence-level upper limits on the amplitude of the axion-induced pseudo-magnetic field over the frequency range $\approx 0.05-20$ Hz, translating to constraints on the linear and quadratic axion-proton couplings for halo densities predicted by gravitational capture models and for the maximum overdensities allowed by planetary ephemerides. In the quadratic coupling case, our limits surpass existing astrophysical bounds by over two orders of magnitude across much of the accessible parameter space.
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Submitted 1 July, 2026; v1 submitted 10 December, 2025;
originally announced December 2025.
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Refractive Index-Correlated Pseudocoloring for Adaptive Color Fusion in Holotomographic Cytology
Authors:
Minseok Lee,
Tal Lifshitz,
Young Ki Lee,
Geon Kim,
Seog Yun Park,
Hayoung Lee,
Juyeon Park,
Eun Kyung Lee,
YongKeun Park
Abstract:
Conventional bright-field (BF) cytology of thyroid fine-needle aspiration biopsy (FNAB) suffers from staining variability and limited subcellular contrast. Here, we present a refractive index-correlated pseudocoloring (RICP) framework that integrates quantitative refractive index (RI) maps obtained by holotomography (HT) with color BF images to enhance diagnostic interpretability. The imaging plat…
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Conventional bright-field (BF) cytology of thyroid fine-needle aspiration biopsy (FNAB) suffers from staining variability and limited subcellular contrast. Here, we present a refractive index-correlated pseudocoloring (RICP) framework that integrates quantitative refractive index (RI) maps obtained by holotomography (HT) with color BF images to enhance diagnostic interpretability. The imaging platform combines a digital micromirror device (DMD)-based HT system with an RGB LED illumination module, enabling simultaneous acquisition of RI tomograms and BF images from PAP-stained thyroid samples. The RICP algorithm adaptively embeds RI-derived structural information into the least-occupied hue channel, preserving color fidelity while enhancing nuclear and cytoplasmic contrast. Applied to benign and malignant thyroid clusters, RICP revealed diagnostically relevant features such as nucleoli, lipid droplets, and nuclear irregularities, and hue-saturation analysis quantitatively differentiated cytological categories. This perceptually grounded, label-free framework bridges conventional color cytology and quantitative optical imaging for improved diagnostic precision.
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Submitted 30 October, 2025;
originally announced October 2025.
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High-Efficiency Quantum-State Detection of ThF$^+$ with Resonance-Enhanced Multiphoton Asymmetric Dissociation
Authors:
Kia Boon Ng,
Sun Yool Park,
Anzhou Wang,
Addison Hartman,
Patricia Hector Hernandez,
Rohan Kompella,
Lan Cheng,
Stephan Malbrunot-Ettenauer,
Jun Ye,
Eric A. Cornell
Abstract:
Efficient quantum-state detection is crucial for many precision control experiments, such as the ongoing effort to probe the electron's electric dipole moment using trapped molecular $^{232}\mathrm{ThF}^+$ ions at JILA. While quantum state detection through state-selective photodissociation has been successfully implemented on this molecule, progress has been hindered by low dissociation efficienc…
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Efficient quantum-state detection is crucial for many precision control experiments, such as the ongoing effort to probe the electron's electric dipole moment using trapped molecular $^{232}\mathrm{ThF}^+$ ions at JILA. While quantum state detection through state-selective photodissociation has been successfully implemented on this molecule, progress has been hindered by low dissociation efficiency. In this work, we perform spectroscopy on the molecule to identify excited states that facilitate more efficient photodissociation. For the most favorable transition, we achieve a dissociation efficiency of 57(14)% with quantum state selectivity. Additionally, we discuss several state detection protocols that leverage favorable excited states that will facilitate simultaneous readout of all EDM relevant states, allowing further improvement of overall statistics.
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Submitted 6 August, 2025;
originally announced August 2025.
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A Multi-Messenger Search for Exotic Field Emission with a Global Magnetometer Network
Authors:
Sami S. Khamis,
Ibrahim A. Sulai,
Paul Hamilton,
S. Afach,
B. C. Buchler,
D. Budker,
N. L. Figueroa,
R. Folman,
D. Gavilán-Martín,
M. Givon,
Z. D. Grujić,
H. Guo,
M. P. Hedges,
D. F. Jackson Kimball,
D. Kim,
E. Klinger,
T. Kornack,
A. Kryemadhi,
N. Kukowski,
G. Lukasiewicz,
H. Masia-Roig,
M. Padniuk,
C. A. Palm,
S. Y. Park,
X. Peng
, et al. (16 additional authors not shown)
Abstract:
Quantum sensor networks in combination with traditional astronomical observations are emerging as a novel modality for multi-messenger astronomy. Here we develop a generic analysis framework that uses a data-driven approach to model the sensitivity of a quantum sensor network to astrophysical signals as a consequence of beyond-the-Standard Model (BSM) physics. The analysis method evaluates correla…
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Quantum sensor networks in combination with traditional astronomical observations are emerging as a novel modality for multi-messenger astronomy. Here we develop a generic analysis framework that uses a data-driven approach to model the sensitivity of a quantum sensor network to astrophysical signals as a consequence of beyond-the-Standard Model (BSM) physics. The analysis method evaluates correlations between sensors to search for BSM signals coincident with astrophysical triggers such as black hole mergers, supernovae, or fast radio bursts. Complementary to astroparticle approaches that search for particlelike signals (e.g. WIMPs), quantum sensors are sensitive to wavelike signals from exotic quantum fields. This analysis method can be applied to networks of different types of quantum sensors, such as atomic clocks, matter-wave interferometers, and nuclear clocks, which can probe many types of interactions between BSM fields and standard model particles.
We use this analysis method to carry out the first direct search utilizing a terrestrial network of precision quantum sensors for BSM fields emitted during a black hole merger. Specifically we use the Global Network of Optical Magnetometers for Exotic physics (GNOME) to perform a search for exotic low-mass field (ELF) bursts generated in coincidence with a gravitational wave signal from a binary black hole merger (GW200311 115853) detected by LIGO/Virgo on the 11th of March 2020. The associated gravitational wave heralds the arrival of the ELF burst that interacts with the spins of fermions in the magnetometers. This enables GNOME to serve as a tool for multi-messenger astronomy. Our search found no significant events, and consequently we place the first lab-based limits on combinations of ELF production and coupling parameters.
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Submitted 20 May, 2025; v1 submitted 18 July, 2024;
originally announced July 2024.
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Development of MMC-based lithium molybdate cryogenic calorimeters for AMoRE-II
Authors:
A. Agrawal,
V. V. Alenkov,
P. Aryal,
H. Bae,
J. Beyer,
B. Bhandari,
R. S. Boiko,
K. Boonin,
O. Buzanov,
C. R. Byeon,
N. Chanthima,
M. K. Cheoun,
J. S. Choe,
S. Choi,
S. Choudhury,
J. S. Chung,
F. A. Danevich,
M. Djamal,
D. Drung,
C. Enss,
A. Fleischmann,
A. M. Gangapshev,
L. Gastaldo,
Y. M. Gavrilyuk,
A. M. Gezhaev
, et al. (84 additional authors not shown)
Abstract:
The AMoRE collaboration searches for neutrinoless double beta decay of $^{100}$Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. The early phases of the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, the AMoRE-II experiment, featuring a large detector array with about 90 kg of $^{100}$Mo isotope, is und…
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The AMoRE collaboration searches for neutrinoless double beta decay of $^{100}$Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. The early phases of the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, the AMoRE-II experiment, featuring a large detector array with about 90 kg of $^{100}$Mo isotope, is under construction. This paper discusses the baseline design and characterization of the lithium molybdate cryogenic calorimeters to be used in the AMoRE-II detector modules. The results from prototype setups that incorporate new housing structures and two different crystal masses (316 g and 517 - 521 g), operated at 10 mK temperature, show energy resolutions (FWHM) of 7.55 - 8.82 keV at the 2.615 MeV $^{208}$Tl $γ$ line, and effective light detection of 0.79 - 0.96 keV/MeV. The simultaneous heat and light detection enables clear separation of alpha particles with a discrimination power of 12.37 - 19.50 at the energy region around $^6$Li(n, $α$)$^3$H with Q-value = 4.785 MeV. Promising detector performances were demonstrated at temperatures as high as 30 mK, which relaxes the temperature constraints for operating the large AMoRE-II array.
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Submitted 3 March, 2025; v1 submitted 16 July, 2024;
originally announced July 2024.
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Projected background and sensitivity of AMoRE-II
Authors:
A. Agrawal,
V. V. Alenkov,
P. Aryal,
J. Beyer,
B. Bhandari,
R. S. Boiko,
K. Boonin,
O. Buzanov,
C. R. Byeon,
N. Chanthima,
M. K. Cheoun,
J. S. Choe,
Seonho Choi,
S. Choudhury,
J. S. Chung,
F. A. Danevich,
M. Djamal,
D. Drung,
C. Enss,
A. Fleischmann,
A. M. Gangapshev,
L. Gastaldo,
Y. M. Gavrilyuk,
A. M. Gezhaev,
O. Gileva
, et al. (81 additional authors not shown)
Abstract:
AMoRE-II aims to search for neutrinoless double beta decay with an array of 423 Li$_2$$^{100}$MoO$_4$ crystals operating in the cryogenic system as the main phase of the Advanced Molybdenum-based Rare process Experiment (AMoRE). AMoRE has been planned to operate in three phases: AMoRE-pilot, AMoRE-I, and AMoRE-II. AMoRE-II is currently being installed at the Yemi Underground Laboratory, located ap…
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AMoRE-II aims to search for neutrinoless double beta decay with an array of 423 Li$_2$$^{100}$MoO$_4$ crystals operating in the cryogenic system as the main phase of the Advanced Molybdenum-based Rare process Experiment (AMoRE). AMoRE has been planned to operate in three phases: AMoRE-pilot, AMoRE-I, and AMoRE-II. AMoRE-II is currently being installed at the Yemi Underground Laboratory, located approximately 1000 meters deep in Jeongseon, Korea. The goal of AMoRE-II is to reach up to $T^{0νββ}_{1/2}$ $\sim$ 6 $\times$ 10$^{26}$ years, corresponding to an effective Majorana mass of 15 - 29 meV, covering all the inverted mass hierarchy regions. To achieve this, the background level of the experimental configurations and possible background sources of gamma and beta events should be well understood. We have intensively performed Monte Carlo simulations using the GEANT4 toolkit in all the experimental configurations with potential sources. We report the estimated background level that meets the 10$^{-4}$counts/(keV$\cdot$kg$\cdot$yr) requirement for AMoRE-II in the region of interest (ROI) and show the projected half-life sensitivity based on the simulation study.
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Submitted 14 October, 2024; v1 submitted 13 June, 2024;
originally announced June 2024.
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What can a GNOME do? Search targets for the Global Network of Optical Magnetometers for Exotic physics searches
Authors:
S. Afach,
D. Aybas Tumturk,
H. Bekker,
B. C. Buchler,
D. Budker,
K. Cervantes,
A. Derevianko,
J. Eby,
N. L. Figueroa,
R. Folman,
D. Gavil'an Martin,
M. Givon,
Z. D. Grujic,
H. Guo,
P. Hamilton,
M. P. Hedges,
D. F. Jackson Kimball,
S. Khamis,
D. Kim,
E. Klinger,
A. Kryemadhi,
X. Liu,
G. Lukasiewicz,
H. Masia-Roig,
M. Padniuk
, et al. (28 additional authors not shown)
Abstract:
Numerous observations suggest that there exist undiscovered beyond-the-Standard-Model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with Standard Model particles in many different ways and assume a variety of possible configurations. Here we present an overview of the Global Network of Optical Magnetometers for Exotic physics searches (GNOM…
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Numerous observations suggest that there exist undiscovered beyond-the-Standard-Model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with Standard Model particles in many different ways and assume a variety of possible configurations. Here we present an overview of the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), our ongoing experimental program designed to test a wide range of exotic physics scenarios. The GNOME experiment utilizes a worldwide network of shielded atomic magnetometers (and, more recently, comagnetometers) to search for spatially and temporally correlated signals due to torques on atomic spins from exotic fields of astrophysical origin. We survey the temporal characteristics of a variety of possible signals currently under investigation such as those from topological defect dark matter (axion-like particle domain walls), axion-like particle stars, solitons of complex-valued scalar fields (Q-balls), stochastic fluctuations of bosonic dark matter fields, a solar axion-like particle halo, and bursts of ultralight bosonic fields produced by cataclysmic astrophysical events such as binary black hole mergers.
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Submitted 4 May, 2023; v1 submitted 2 May, 2023;
originally announced May 2023.
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A new bound on the electron's electric dipole moment
Authors:
Tanya S. Roussy,
Luke Caldwell,
Trevor Wright,
William B. Cairncross,
Yuval Shagam,
Kia Boon Ng,
Noah Schlossberger,
Sun Yool Park,
Anzhou Wang,
Jun Ye,
Eric A. Cornell
Abstract:
The Standard Model cannot explain the dominance of matter over anti-matter in our universe. This imbalance indicates undiscovered physics that violates combined CP symmetry. Many extensions to the Standard Model seek to explain the imbalance by predicting the existence of new particles. Vacuum fluctuations of the fields associated with these new particles can interact with known particles and make…
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The Standard Model cannot explain the dominance of matter over anti-matter in our universe. This imbalance indicates undiscovered physics that violates combined CP symmetry. Many extensions to the Standard Model seek to explain the imbalance by predicting the existence of new particles. Vacuum fluctuations of the fields associated with these new particles can interact with known particles and make small modifications to their properties; for example, particles which violate CP symmetry will induce an electric dipole moment of the electron (eEDM). The size of the induced eEDM is dependent on the masses of the new particles and their coupling to the Standard Model. To date, no eEDM has been detected, but increasingly precise measurements probe new physics with higher masses and weaker couplings. Here we present the most precise measurement yet of the eEDM using electrons confined inside molecular ions, subjected to a huge intra-molecular electric field, and evolving coherently for up to 3 s. Our result is consistent with zero and improves on the previous best upper bound by a factor $\sim2.4$. Our sensitivity to $10^{-19}$ eV shifts in molecular ions provides constraints on broad classes of new physics above $10^{13}$ eV, well beyond the direct reach of the LHC or any other near- or medium-term particle collider.
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Submitted 27 December, 2022; v1 submitted 22 December, 2022;
originally announced December 2022.
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Systematic and statistical uncertainty evaluation of the HfF$^+$ electron electric dipole moment experiment
Authors:
Luke Caldwell,
Tanya S. Roussy,
Trevor Wright,
William B. Cairncross,
Yuval Shagam,
Kia Boon Ng,
Noah Schlossberger,
Sun Yool Park,
Anzhou Wang,
Jun Ye,
Eric A. Cornell
Abstract:
We have completed a new precision measurement of the electron's electric dipole moment using trapped HfF$^+$ in rotating bias fields. We report on the accuracy evaluation of this measurement, describing the mechanisms behind our systematic shifts. Our systematic uncertainty is reduced by a factor of 30 compared to the first generation of this measurement. Our combined statistical and systematic ac…
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We have completed a new precision measurement of the electron's electric dipole moment using trapped HfF$^+$ in rotating bias fields. We report on the accuracy evaluation of this measurement, describing the mechanisms behind our systematic shifts. Our systematic uncertainty is reduced by a factor of 30 compared to the first generation of this measurement. Our combined statistical and systematic accuracy is improved by a factor of 2 relative to any previous measurement.
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Submitted 22 December, 2022; v1 submitted 22 December, 2022;
originally announced December 2022.
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Spectroscopy on the eEDM-sensitive states of ThF$^+$
Authors:
Kia Boon Ng,
Yan Zhou,
Lan Cheng,
Noah Schlossberger,
Sun Yool Park,
Tanya S. Roussy,
Luke Caldwell,
Yuval Shagam,
Antonio J. Vigil,
Eric A. Cornell,
Jun Ye
Abstract:
An excellent candidate molecule for the measurement of the electron's electric dipole moment (eEDM) is thorium monofluoride (ThF$^+$) because the eEDM-sensitive state, $^3Δ_1$, is the electronic ground state, and thus is immune to decoherence from spontaneous decay. We perform spectroscopy on $X\,^3Δ_1$ to extract three spectroscopic constants crucial to the eEDM experiment: the hyperfine coupling…
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An excellent candidate molecule for the measurement of the electron's electric dipole moment (eEDM) is thorium monofluoride (ThF$^+$) because the eEDM-sensitive state, $^3Δ_1$, is the electronic ground state, and thus is immune to decoherence from spontaneous decay. We perform spectroscopy on $X\,^3Δ_1$ to extract three spectroscopic constants crucial to the eEDM experiment: the hyperfine coupling constant, the molecular frame electric dipole moment, and the magnetic $g$-factor. To understand the impact of thermal blackbody radiation on the vibrational ground state, we study the lifetime of the first excited vibrational manifold of $X\,^3Δ_1$. We perform ab initio calculations, compare them to our results, and discuss prospects for using ThF$^+$ in a new eEDM experiment at JILA.
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Submitted 2 February, 2022;
originally announced February 2022.
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Alpha backgrounds in the AMoRE-Pilot experiment
Authors:
V. Alenkov,
H. W. Bae,
J. Beyer,
R. S. Boiko,
K. Boonin,
O. Buzanov,
N. Chanthima,
M. K. Cheoun,
S. H. Choi,
F. A. Danevich,
M. Djamal,
D. Drung,
C. Enss,
A. Fleischmann,
A. Gangapshev,
L. Gastaldo,
Yu. M. Gavriljuk,
A. Gezhaev,
V. D. Grigoryeva,
V. Gurentsov,
D. H. Ha,
C. Ha,
E. J. Ha,
I. Hahn,
E. J. Jeon
, et al. (81 additional authors not shown)
Abstract:
The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of $^{100}$Mo, with the purpose of investigating the level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface $α$ decays on the crystals themselves or nearby materials can deposit…
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The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of $^{100}$Mo, with the purpose of investigating the level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface $α$ decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the $Q$-value of the decay itself and may fall in the region of interest (ROI). To understand these background events, we studied backgrounds from radioactive contaminations internal to and on the surface of the crystals or nearby materials with Geant4-based Monte Carlo simulations. In this study, we report on the measured $α$ energy spectra fitted with the corresponding simulated spectra for six crystal detectors, where sources of background contributions could be identified through high energy $α$ peaks and continuum parts in the energy spectrum for both internal and surface contaminations. We determine the low-energy contributions from internal and surface $α$ contaminations by extrapolating from the $α$ background fitting model.
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Submitted 5 December, 2022; v1 submitted 16 July, 2021;
originally announced July 2021.
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Search for topological defect dark matter with a global network of optical magnetometers
Authors:
Samer Afach,
Ben C. Buchler,
Dmitry Budker,
Conner Dailey,
Andrei Derevianko,
Vincent Dumont,
Nataniel L. Figueroa,
Ilja Gerhardt,
Zoran D. Grujić,
Hong Guo,
Chuanpeng Hao,
Paul S. Hamilton,
Morgan Hedges,
Derek F. Jackson Kimball,
Dongok Kim,
Sami Khamis,
Thomas Kornack,
Victor Lebedev,
Zheng-Tian Lu,
Hector Masia-Roig,
Madeline Monroy,
Mikhail Padniuk,
Christopher A. Palm,
Sun Yool Park,
Karun V. Paul
, et al. (24 additional authors not shown)
Abstract:
Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared to the galaxy but much larger than the Earth. Here, we report the results of a search for transient signals f…
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Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared to the galaxy but much larger than the Earth. Here, we report the results of a search for transient signals from axion-like particle domain walls with the Global Network of Optical Magnetometers for Exotic physics searches (GNOME). We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of data from a continuous month-long operation of the GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios.
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Submitted 7 December, 2021; v1 submitted 26 February, 2021;
originally announced February 2021.
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Measurement of the Background Activities of a 100Mo-enriched Powder Sample for an AMoRE Crystal Material by using Fourteen High-Purity Germanium Detectors
Authors:
S. Y. Park,
K. I. Hahn,
W. G. Kang,
V. Kazalov,
G. W. Kim,
Y. D. Kim,
E. K. Lee,
M. H. Lee,
D. S. Leonard
Abstract:
The Advanced Molybdenum-based Rare process Experiment in its second phase (AMoRE-II) will search for neutrinoless double-beta (0ν\b{eta}\b{eta}) decay of 100Mo in 200 kg of molybdate crystals. To achieve the zero-background level in the energy range of the double-beta decay Q-value of 100Mo, the radioactive contamination levels in AMoRE crystals should be low. 100EnrMoO3 powder, which is enriched…
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The Advanced Molybdenum-based Rare process Experiment in its second phase (AMoRE-II) will search for neutrinoless double-beta (0ν\b{eta}\b{eta}) decay of 100Mo in 200 kg of molybdate crystals. To achieve the zero-background level in the energy range of the double-beta decay Q-value of 100Mo, the radioactive contamination levels in AMoRE crystals should be low. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is used to grow the AMoRE crystals. A shielded array of fourteen high-purity germanium detectors with 70% relative efficiency each was used for the measurement of background activities in a sample of 9.6-kg powder. The detector system named CAGe located at the Yangyang underground laboratory was designed for measuring low levels of radioactivity from natural radioisotopes or cosmogenic nuclides such as 228Ac, 228Th, 226Ra, 88Y, and 40K. The activities of 228Ac and 228Th in the powder sample were 0.88 \pm 0.12 mBq/kg and 0.669 \pm 0.087 mBq/kg, respectively. The activity of 226Ra was measured to be 1.50 \pm 0.23 mBq/kg. The activity of 88Y was 0.101 \pm 0.016 mBq/kg. The activity of 40K was found as 36.0 \pm 4.1 mBq/kg.
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Submitted 4 September, 2020;
originally announced September 2020.
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Development of an array of HPGe detectors with 980% relative efficiency
Authors:
D. S. Leonard,
I. S. Hahn,
W. G. Kang,
V. Kazalov,
G. W. Kim,
Y. D. Kim,
E. K. Lee,
M. H. Lee,
S. Y. Park,
E. Sala
Abstract:
Searches for new physics push experiments to look for increasingly rare interactions. As a result, detectors require increasing sensitivity and specificity, and materials must be screened for naturally occurring, background-producing radioactivity. Furthermore the detectors used for screening must approach the sensitivities of the physics-search detectors themselves, thus motivating iterative deve…
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Searches for new physics push experiments to look for increasingly rare interactions. As a result, detectors require increasing sensitivity and specificity, and materials must be screened for naturally occurring, background-producing radioactivity. Furthermore the detectors used for screening must approach the sensitivities of the physics-search detectors themselves, thus motivating iterative development of detectors capable of both physics searches and background screening. We report on the design, installation, and performance of a novel, low-background, fourteen-element high-purity germanium detector named the CAGe (CUP Array of Germanium), installed at the Yangyang underground laboratory in Korea.
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Submitted 1 September, 2020;
originally announced September 2020.
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The ELFIN Mission
Authors:
V. Angelopoulos,
E. Tsai,
L. Bingley,
C. Shaffer,
D. L. Turner,
A. Runov,
W. Li,
J. Liu,
A. V. Artemyev,
X. -J. Zhang,
R. J. Strangeway,
R. E. Wirz,
Y. Y. Shprits,
V. A. Sergeev,
R. P. Caron,
M. Chung,
P. Cruce,
W. Greer,
E. Grimes,
K. Hector,
M. J. Lawson,
D. Leneman,
E. V. Masongsong,
C. L. Russell,
C. Wilkins
, et al. (57 additional authors not shown)
Abstract:
The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (~93deg inclination), nearly circular, low-Earth (~450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism…
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The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (~93deg inclination), nearly circular, low-Earth (~450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (~90min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50keV to 5MeV electrons with deltaE/E<40% and a fluxgate magnetometer (FGM) on a ~72cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5Hz Nyquist (nominally) with <0.3nT/sqrt(Hz) noise at 1Hz. The spinning satellites (T_spin~3s) are equipped with magnetorquers that permit spin-up/down and reorientation maneuvers. The spin axis is placed normal to the orbit plane, allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250keV-5MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018.
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Submitted 16 June, 2020; v1 submitted 13 June, 2020;
originally announced June 2020.
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Growth and development of pure Li2MoO4 crystals for rare event experiment at CUP
Authors:
J. K. Son,
J. S. Choe,
O. Gileva,
I. S. Hahn,
W. G. Kang,
D. Y. Kim,
G. W. Kim,
H. J. Kim,
Y. D. Kim,
C. H. Lee,
E. K. Lee,
M. H. Lee,
D. S. Leonard,
H. K. Park,
S. Y. Park,
S. J. Ra,
K. A. Shin
Abstract:
The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0ν\b{eta}\b{eta}) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0ν\b{eta}\b{eta} signal. For the last few years, we have been growing and studying…
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The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0ν\b{eta}\b{eta}) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0ν\b{eta}\b{eta} signal. For the last few years, we have been growing and studying Li2MoO4 crystals in a clean-environment facility to minimize external contamination during the crystal growth. Before growing Li2100MoO4 crystal, we have studied Li2natMoO4 crystal growth by a conventional Czochralski (CZ) grower. We grew a few different kinds of Li2natMO4 crystals using different raw materials in a campaign to minimize impurities. We prepared the fused Al2O3 refractories for the growth of ingots. Purities of the grown crystals were measured with high purity germanium detectors and by inductively coupled plasma mass spectrometry. The results show that the Li2MoO4 crystal has purity levels suitable for rare-event experiments. In this study, we present the growth of Li2MoO4 crystals at CUP and their purities.
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Submitted 14 May, 2020;
originally announced May 2020.
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First Results from the AMoRE-Pilot neutrinoless double beta decay experiment
Authors:
V. Alenkov,
H. W. Bae,
J. Beyer,
R. S. Boiko,
K. Boonin,
O. Buzanov,
N. Chanthima,
M. K. Cheoun,
D. M. Chernyak,
J. S. Choe,
S. Choi,
F. A. Danevich,
M. Djamal,
D. Drung,
C. Enss,
A. Fleischmann,
A. M. Gangapshev,
L. Gastaldo,
Yu. M. Gavriljuk,
A. M. Gezhaev,
V. D. Grigoryeva,
V. I. Gurentsov,
O. Gylova,
C. Ha,
D. H. Ha
, et al. (84 additional authors not shown)
Abstract:
The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search for neutrinoless double beta decay (0$νββ$) of $^{100}$Mo with $\sim$100 kg of $^{100}$Mo-enriched molybdenum embedded in cryogenic detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from $^{48}$Ca-de…
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The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search for neutrinoless double beta decay (0$νββ$) of $^{100}$Mo with $\sim$100 kg of $^{100}$Mo-enriched molybdenum embedded in cryogenic detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from $^{48}$Ca-depleted calcium and $^{100}$Mo-enriched molybdenum ($^{48\textrm{depl}}$Ca$^{100}$MoO$_4$). The simultaneous detection of heat(phonon) and scintillation (photon) signals is realized with high resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin temperatures. This stage of the project is carried out in the Yangyang underground laboratory at a depth of 700 m. We report first results from the AMoRE-Pilot $0νββ$ search with a 111 kg$\cdot$d live exposure of $^{48\textrm{depl}}$Ca$^{100}$MoO$_4$ crystals. No evidence for $0νββ$ decay of $^{100}$Mo is found, and a upper limit is set for the half-life of 0$νββ$ of $^{100}$Mo of $T^{0ν}_{1/2} > 9.5\times10^{22}$ y at 90% C.L.. This limit corresponds to an effective Majorana neutrino mass limit in the range $\langle m_{ββ}\rangle\le(1.2-2.1)$ eV.
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Submitted 7 May, 2019; v1 submitted 22 March, 2019;
originally announced March 2019.
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Reinforced magnetic properties of Ni-doped BiFeO3 ceramic
Authors:
J. S. Hwang,
Y. J. Yoo,
J. -H. Kang,
K. H. Lee,
B. W. Lee,
S. Y. Park,
Y. P. Lee
Abstract:
Multiferroic materials attract considerable interest because of the wide range of potential applications such as spintronic devices, data storage and sensors. As a strong candidate for the applications among the limited list of single-phase multiferroic materials, BiFeO3 (BFO) is a quite attractive material due to its multiferroic properties at room temperature (RT). However, BFO is widely known t…
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Multiferroic materials attract considerable interest because of the wide range of potential applications such as spintronic devices, data storage and sensors. As a strong candidate for the applications among the limited list of single-phase multiferroic materials, BiFeO3 (BFO) is a quite attractive material due to its multiferroic properties at room temperature (RT). However, BFO is widely known to have large leakage current and small spontaneous polarization due to the existence of crystalline defects such as oxygen vacancies. Furthermore, the magnetic moment of pure BFO is very weak owing to its antiferromagnetic nature. In this paper, the effects of Ni2+ substitution on the magnetic properties of bulk BFO have been investigated. BFO, and BiFe0.99Ni0.01O3, BiFe0.98Ni0.02O3 and BiFe0.97Ni0.03O3 (BFNO: Ni-doped BFO) ceramics were prepared by solid-state reaction and rapid sintering, and analyzed by structural and magnetic-property measurements. The leakage current density was measured at RT by using a standard ferroelectric tester. All the Ni-doped BFO exhibit the similar rhombohedral perovskite structure (R3c) to that of BFO. The magnetic properties of Ni-doped BFO are much enhanced with respect to BFO prepared at the same conditions, since the enhanced ferromagnetic interaction is caused by the Fe/Ni coupling.
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Submitted 23 May, 2016;
originally announced May 2016.