Browsing by Author "J.H. Chen"

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Background rejection of TEXONO experiment to explore the sub-keV energy region with HPGe detector
(Scientific Publishers, 2017) M.K. Singh; V. Sharma; L. Singh; J.H. Chen; V. Singh; V.S. Subrahmanyam; A.K. Soma; H.T. Wong
To observe the neutrino–nucleus coherent scattering as well as for dark matter search, a detection system with ultra-low energy high purity germanium detector has been set up by the TEXONO Collaboration in Kuo-Sheng Nuclear Power Plant. Owing to the weak nature and small recoil energy of these rare events, understanding of background sources and their contribution to the energy spectrum are the key factors in this experiment. In this report, we will focus in detail on the different sources of backgrounds in the TEXONO experiment and the techniques used to reject/minimize them. © 2017, Indian Association for the Cultivation of Science.
Bulk and surface event identification in p-type germanium detectors
(Elsevier B.V., 2018) L.T. Yang; H.B. Li; H.T. Wong; M. Agartioglu; J.H. Chen; L.P. Jia; H. Jiang; J. Li; F.K. Lin; S.T. Lin; S.K. Liu; J.L. Ma; B. Sevda; V. Sharma; L. Singh; M.K. Singh; M.K. Singh; A.K. Soma; A. Sonay; S.W. Yang; L. Wang; Q. Wang; Q. Yue; W. Zhao
The p-type point-contact germanium detectors have been adopted for light dark matter WIMP searches and the studies of low energy neutrino physics. These detectors exhibit anomalous behavior to events located at the surface layer. The previous spectral shape method to identify these surface events from the bulk signals relies on spectral shape assumptions and the use of external calibration sources. We report an improved method in separating them by taking the ratios among different categories of in situ event samples as calibration sources. Data from CDEX-1 and TEXONO experiments are re-examined using the ratio method. Results are shown to be consistent with the spectral shape method. © 2018 Elsevier B.V.
Characterization and performance of germanium detectors with sub-keV sensitivities for neutrino and dark matter experiments
(Elsevier B.V., 2016) A.K. Soma; M.K. Singh; L. Singh; G. Kiran Kumar; F.K. Lin; Q. Du; H. Jiang; S.K. Liu; J.L. Ma; V. Sharma; L. Wang; Y.C. Wu; L.T. Yang; W. Zhao; M. Agartioglu; G. Asryan; Y.Y. Chang; J.H. Chen; Y.C. Chuang; M. Deniz; C.L. Hsu; Y.H. Hsu; T.R. Huang; L.P. Jia; S. Kerman; H.B. Li; J. Li; F.T. Liao; H.Y. Liao; C.W. Lin; S.T. Lin; V. Marian; X.C. Ruan; B. Sevda; Y.T. Shen; M.K. Singh; V. Singh; A. Sonay; J. Su; V.S. Subrahmanyam; C.H. Tseng; J.J. Wang; H.T. Wong; Y. Xu; S.W. Yang; C.X. Yu; Q. Yue; M. Zeyrek
Germanium ionization detectors with sensitivities as low as 100 eVee (electron-equivalent energy) open new windows for studies on neutrino and dark matter physics. The relevant physics subjects are summarized. The detectors have to measure physics signals whose amplitude is comparable to that of pedestal electronic noise. To fully exploit this new detector technique, various experimental issues including quenching factors, energy reconstruction and calibration, signal triggering and selection as well as evaluation of their associated efficiencies have to be attended. The efforts and results of a research program to address these challenges are presented. © 2016 Elsevier B.V.
Constraints on axion couplings from the CDEX-1 experiment at the China Jinping Underground Laboratory
(American Physical Society, 2017) S.K. Liu; Q. Yue; K.J. Kang; J.P. Cheng; H.T. Wong; Y.J. Li; H.B. Li; S.T. Lin; J.P. Chang; J.H. Chen; N. Chen; Q.H. Chen; Y.H. Chen; Z. Deng; Q. Du; H. Gong; H.J. He; Q.J. He; H.X. Huang; H. Jiang; J.M. Li; J. Li; J. Li; X. Li; X.Q. Li; X.Y. Li; Y.L. Li; F.K. Lin; L.C. Lü; H. Ma; J.L. Ma; S.J. Mao; J.Q. Qin; J. Ren; J. Ren; X.C. Ruan; V. Sharma; M.B. Shen; L. Singh; M.K. Singh; A.K. Soma; J. Su; C.J. Tang; J.M. Wang; L. Wang; Q. Wang; S.Y. Wu; Y.C. Wu; Y.C. Wu; Z.Z. Xianyu; R.Q. Xiao; H.Y. Xing; F.Z. Xu; Y. Xu; X.J. Xu; T. Xue; C.W. Yang; L.T. Yang; S.W. Yang; N. Yi; C.X. Yu; H. Yu; X.Z. Yu; X.H. Zeng; Z. Zeng; L. Zhang; Y.H. Zhang; M.G. Zhao; W. Zhao; Z.Y. Zhou; J.J. Zhu; W.B. Zhu; X.Z. Zhu; Z.H. Zhu
We report the results of searches for solar axions and galactic dark matter axions or axionlike particles with the CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg days of data from a p-type point-contact germanium detector. The data are compatible with the background model, and no excess signals are observed. Limits of solar axions on the model-independent coupling gAe<2.5×10-11 from Compton, bremsstrahlung, atomic-recombination, and deexcitation channels and gANeff×gAe<6.4×10-17 from a Fe57 M1 transition at 90% confidence level are derived. Within the framework of the Dine-Fischler-Srednicki-Zhitnitskiy and Kim-Shifman-Vainshtein-Zakharov models, our results exclude the axion mass heavier than 0.9 and 177 eV/c2, respectively. The derived constraints for dark matter axions below 1 keV improve over the previous results. © 2017 American Physical Society.
Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jinping Underground Laboratory
(American Physical Society, 2019) Z.Z. Liu; Q. Yue; L.T. Yang; K.J. Kang; Y.J. Li; H.T. Wong; M. Agartioglu; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; J.P. Cheng; Z. Deng; Q. Du; H. Gong; X.Y. Guo; Q.J. Guo; L. He; S.M. He; J.W. Hu; Q.D. Hu; H.X. Huang; L.P. Jia; H. Jiang; H.B. Li; H. Li; J.M. Li; J. Li; X. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; S.K. Liu; Y.D. Liu; Y.Y. Liu; H. Ma; J.L. Ma; Y.C. Mao; J.H. Ning; H. Pan; N.C. Qi; J. Ren; X.C. Ruan; V. Sharma; Z. She; L. Singh; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; L. Wang; Q. Wang; Y. Wang; Y.X. Wang; S.Y. Wu; Y.C. Wu; H.Y. Xing; Y. Xu; T. Xue; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; M. Zeng; Z. Zeng; F.S. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu
We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (mχ) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg day exposure and 250 eVee threshold for AM analysis. The sensitive windows in mχ are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σχNSI at 90% confidence level are derived as 2×10-32∼7×10-35 cm2 for TI analysis at mχ∼50-180 MeV/c2, and 3×10-32∼9×10-38 cm2 for AM analysis at mχ∼75 MeV/c2-3.0 GeV/c2. .
Direct Detection Constraints on Dark Photons with the CDEX-10 Experiment at the China Jinping Underground Laboratory
(American Physical Society, 2020) Z. She; L.P. Jia; Q. Yue; H. Ma; K.J. Kang; Y.J. Li; M. Agartioglu; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; J.P. Cheng; W.H. Dai; Z. Deng; X.P. Geng; H. Gong; P. Gu; Q.J. Guo; X.Y. Guo; L. He; S.M. He; H.T. He; J.W. Hu; T.C. Huang; H.X. Huang; H.B. Li; H. Li; J.M. Li; J. Li; M.X. Li; X. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; S.K. Liu; Y.D. Liu; Y.Y. Liu; Z.Z. Liu; Y.C. Mao; Q.Y. Nie; J.H. Ning; H. Pan; N.C. Qi; C.K. Qiao; J. Ren; X.C. Ruan; B. Sevda; C.S. Shang; V. Sharma; L. Singh; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; L. Wang; Q. Wang; Y. Wang; Y.X. Wang; Z. Wang; H.T. Wong; S.Y. Wu; H.Y. Xing; Y. Xu; T. Xue; Y.L. Yan; L.T. Yang; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; M. Zeng; Z. Zeng; B.T. Zhang; L. Zhang; F.S. Zhang; Z.Y. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu
We report constraints on the dark photon effective kinetic mixing parameter (κ) with data taken from two p-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on κ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (mV) from 10 to 300 eV/c2 in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90% confidence level with mV from 0.1 to 4.0 keV/c2 are set from 449.6 kg-day data, with a minimum of κ=1.3×10-15 at mV=200 eV/c2. © 2020 authors. Published by the American Physical Society.
Improved limits on solar axions and bosonic dark matter from the CDEX-1B experiment using the profile likelihood ratio method
(American Physical Society, 2020) Y. Wang; Q. Yue; S.K. Liu; K.J. Kang; Y.J. Li; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; J.P. Cheng; W.H. Dai; Z. Deng; X.P. Geng; H. Gong; P. Gu; X.Y. Guo; H.T. He; L. He; S.M. He; J.W. Hu; H.X. Huang; T.C. Huang; L.P. Jia; H.B. Li; H. Li; M.X. Li; J.M. Li; J. Li; X. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; Y.D. Liu; Y.Y. Liu; Z.Z. Liu; H. Ma; Q.Y. Nie; J.H. Ning; H. Pan; N.C. Qi; C.K. Qiao; J. Ren; X.C. Ruan; V. Sharma; Z. She; L. Singh; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; L. Wang; Q. Wang; Z. Wang; H.T. Wong; S.Y. Wu; Y.C. Wu; H.Y. Xing; Y. Xu; T. Xue; Y.L. Yan; L.T. Yang; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; X.H. Zeng; M. Zeng; Z. Zeng; B.T. Zhang; F.S. Zhang; L. Zhang; Z.Y. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu
We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling gAe<2.48×10-11 from Compton, bremsstrahlung, atomic-recombination, and deexcitation channels and gANeff×gAe<4.14×10-17 from a Fe57 M1 transition at 90% confidence level. © 2020 authors.
Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment
(American Physical Society, 2018) H. Jiang; L.P. Jia; Q. Yue; K.J. Kang; J.P. Cheng; Y.J. Li; H.T. Wong; M. Agartioglu; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; Z. Deng; Q. Du; H. Gong; L. He; J.W. Hu; Q.D. Hu; H.X. Huang; H.B. Li; H. Li; J.M. Li; J. Li; X. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; S.K. Liu; Y.D. Liu; Y.Y. Liu; Z.Z. Liu; H. Ma; J.L. Ma; H. Pan; J. Ren; X.C. Ruan; B. Sevda; V. Sharma; M.B. Shen; L. Singh; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; J.M. Wang; L. Wang; Q. Wang; Y. Wang; S.Y. Wu; Y.C. Wu; H.Y. Xing; Y. Xu; T. Xue; L.T. Yang; S.W. Yang; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; X.H. Zeng; M. Zeng; Z. Zeng; F.S. Zhang; Y.H. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu; Z.H. Zhu
We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10-42 and 3×10-36 cm2 at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (mχ) of 5 GeV/c2 are achieved. The lower reach of mχ is extended to 2 GeV/c2. © 2018 authors. Published by the American Physical Society.
Neutron background measurements with a hybrid neutron detector at the Kuo-Sheng Reactor Neutrino Laboratory
(American Physical Society, 2018) A. Sonay; M. Deniz; H.T. Wong; M. Agartioglu; G. Asryan; J.H. Chen; S. Kerman; H.B. Li; J. Li; F.K. Lin; S.T. Lin; B. Sevda; V. Sharma; L. Singh; M.K. Singh; M.K. Singh; V. Singh; A.K. Soma; S.W. Yang; Q. Yue; I.O. Ylldlrlm; M. Zeyrek
We report in situ neutron background measurements at the Kuo-Sheng Reactor Neutrino Laboratory (KSNL) by a hybrid neutron detector (HND) with a data size of 33.8 days under shielding configurations identical to those used during the neutrino physics data taking. The HND consists of BC-501A liquid and BC-702 phosphor powder scintillation neutron detectors, which are sensitive to both fast and thermal neutrons, respectively. Neutron-induced events for the two channels are identified and differentiated by pulse shape analysis, such that the backgrounds of both are simultaneously measured. The fast neutron fluxes are derived by an iterative unfolding algorithm. Neutron-induced backgrounds in the germanium detector under the same fluxes, due to both cosmic rays and ambient radioactivity, are derived and compared with the measurements. The results are valuable to background understanding of the neutrino data at the KSNL. In particular, neutron-induced background events due to ambient radioactivity as well as from reactor operation are negligible compared to intrinsic cosmogenic activity and ambient γ activity. The detector concept and analysis procedures are applicable to neutron background characterization in similar rare-event experiments. © 2018 American Physical Society.
Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory
(American Physical Society, 2019) L.T. Yang; H.B. Li; Q. Yue; H. Ma; K.J. Kang; Y.J. Li; H.T. Wong; M. Agartioglu; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; J.P. Cheng; Z. Deng; Q. Du; H. Gong; Q.J. Guo; L. He; J.W. Hu; Q.D. Hu; H.X. Huang; L.P. Jia; H. Jiang; H. Li; J.M. Li; J. Li; X. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; S.K. Liu; Y.D. Liu; Y.Y. Liu; Z.Z. Liu; J.L. Ma; Y.C. Mao; H. Pan; J. Ren; X.C. Ruan; V. Sharma; Z. She; M.B. Shen; L. Singh; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; J.M. Wang; L. Wang; Q. Wang; Y. Wang; Y.X. Wang; S.Y. Wu; Y.C. Wu; H.Y. Xing; Y. Xu; T. Xue; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; X.H. Zeng; M. Zeng; Z. Zeng; F.S. Zhang; Y.H. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu; Z.H. Zhu
We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (mχ) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at mχ<6 GeV/c2 among WIMP AM measurements to date. © 2019 authors. Published by the American Physical Society.
Search of low-mass WIMPs with a p -type point contact germanium detector in the CDEX-1 experiment
(American Physical Society, 2016) W. Zhao; Q. Yue; K.J. Kang; J.P. Cheng; Y.J. Li; H.T. Wong; S.T. Lin; J.P. Chang; J.H. Chen; Q.H. Chen; Y.H. Chen; Z. Deng; Q. Du; H. Gong; X.Q. Hao; H.J. He; Q.J. He; H.X. Huang; T.R. Huang; H. Jiang; H.B. Li; J. Li; J. Li; J.M. Li; X. Li; X.Y. Li; Y.L. Li; F.K. Lin; S.K. Liu; L.C. Lü; H. Ma; J.L. Ma; S.J. Mao; J.Q. Qin; J. Ren; J. Ren; X.C. Ruan; V. Sharma; M.B. Shen; L. Singh; M.K. Singh; A.K. Soma; J. Su; C.J. Tang; J.M. Wang; L. Wang; Q. Wang; S.Y. Wu; Y.C. Wu; Z.Z. Xianyu; R.Q. Xiao; H.Y. Xing; F.Z. Xu; Y. Xu; X.J. Xu; T. Xue; L.T. Yang; S.W. Yang; N. Yi; C.X. Yu; H. Yu; X.Z. Yu; M. Zeng; X.H. Zeng; Z. Zeng; L. Zhang; Y.H. Zhang; M.G. Zhao; Z.Y. Zhou; J.J. Zhu; W.B. Zhu; X.Z. Zhu; Z.H. Zhu
The CDEX-1 experiment conducted a search of low-mass (<10 GeV/c2) weakly interacting massive particles dark matter at the China Jinping Underground Laboratory using a p-type point-contact germanium detector with a fiducial mass of 915 g at a physics analysis threshold of 475 eVee. We report the hardware setup, detector characterization, data acquisition, and analysis procedures of this experiment. No excess of unidentified events is observed after the subtraction of the known background. Using 335.6 kg-days of data, exclusion constraints on the weakly interacting massive particle-nucleon spin-independent and spin-dependent couplings are derived. © 2016 American Physical Society.
Studies of the Earth shielding effect to direct dark matter searches at the China Jinping Underground Laboratory
(American Physical Society, 2022) Z.Z. Liu; L.T. Yang; Q. Yue; C.H. Yeh; K.J. Kang; Y.J. Li; M. Agartioglu; H.P. An; J.P. Chang; J.H. Chen; Y.H. Chen; J.P. Cheng; W.H. Dai; Z. Deng; C.H. Fang; X.P. Geng; H. Gong; X.Y. Guo; Q.J. Guo; L. He; S.M. He; J.W. Hu; H.X. Huang; T.C. Huang; H.T. Jia; X. Jiang; H.B. Li; J.M. Li; J. Li; R.M.J. Li; X.Q. Li; Y.L. Li; B. Liao; F.K. Lin; S.T. Lin; S.K. Liu; Y. Liu; Y.D. Liu; Y.Y. Liu; H. Ma; Y.C. Mao; Q.Y. Nie; J.H. Ning; H. Pan; N.C. Qi; J. Ren; X.C. Ruan; V. Sharma; Z. She; K. Saraswat; M.K. Singh; T.X. Sun; C.J. Tang; W.Y. Tang; Y. Tian; G.F. Wang; L. Wang; Q. Wang; Y. Wang; Y.X. Wang; Z. Wang; H.T. Wong; S.Y. Wu; Y.C. Wu; H.Y. Xing; Y. Xu; T. Xue; Y.L. Yan; N. Yi; C.X. Yu; H.J. Yu; J.F. Yue; M. Zeng; Z. Zeng; B.T. Zhang; F.S. Zhang; K.K. Zhang; Z.H. Zhang; Z.Y. Zhang; M.G. Zhao; J.F. Zhou; Z.Y. Zhou; J.J. Zhu
Dark matter direct detection experiments mostly operate at deep underground laboratories. It is necessary to consider shielding effect of the Earth, especially for dark matter particles interacting with a large cross section. We analyzed and simulated the Earth shielding effect for dark matter at the China Jinping Underground Laboratory (CJPL) with a simulation package, CJPL Earth Shielding Simulation code (CJPL_ESS), which is applicable to other underground locations. The further constraints on the χ-N cross section exclusion regions are derived based on the studies with CDEX experiment data. © 2022 authors. Published by the American Physical Society.