We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge....We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge.A total of 504.3 kg⋅day effective exposure data was accumulated.The anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was realized.The lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<mββ><3.2–7.5 eV.展开更多
Over the past few years,phonon detectors have emerged as a prevailing technology for detecting lowmass dark matter due to their low thresholds and high resolution.These detectors,which employ either dual-phase detecto...Over the past few years,phonon detectors have emerged as a prevailing technology for detecting lowmass dark matter due to their low thresholds and high resolution.These detectors,which employ either dual-phase detectors combining phonon-light or phonon-electron interactions,have significantly advanced direct dark matter detection efforts.Argon,as a low-background and high-reserve detection medium,has also played a crucial role in this field.Both liquid-argon single-phase detectors and gas-liquid two-phase time projection chambers(TPCs)have contributed substantially to the direct detection of high-mass dark matter.By integrating these distinct detector types,the upper limits of the corresponding mass cross-section in dark matter detection can be lowered.We propose a phonon detector utilizing solid argon as the absorber,which combines the advantages of both aforementioned detector types.However,due to the requirement for an ultra-low temperature environment in the tens of millikelvin(mK)range,experimental investigations of solid argon phonon detector performance are currently constrained by technical limitations.Therefore,the performance analysis of the solid argon phonon detector presented in this study is only based on sapphire phonon detectors.Although there may be discrepancies between this approximation and the actual performance,the intrinsic characteristics of phonon detectors permit a qualitative evaluation of the solid argon phonon detector's potential capabilities.展开更多
基金Supported by the National Key Research and Development Program of China(2017YFA0402201,2022YFA1604701,2022YFA1605000)the National Natural Science Foundation of China(12322511,12175112,12005111,11725522)。
文摘We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge.A total of 504.3 kg⋅day effective exposure data was accumulated.The anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was realized.The lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<mββ><3.2–7.5 eV.
基金the National Key Research and Development Program of China(2017YFA0402203)the National Natural Science Foundation of China(12075161)。
文摘Over the past few years,phonon detectors have emerged as a prevailing technology for detecting lowmass dark matter due to their low thresholds and high resolution.These detectors,which employ either dual-phase detectors combining phonon-light or phonon-electron interactions,have significantly advanced direct dark matter detection efforts.Argon,as a low-background and high-reserve detection medium,has also played a crucial role in this field.Both liquid-argon single-phase detectors and gas-liquid two-phase time projection chambers(TPCs)have contributed substantially to the direct detection of high-mass dark matter.By integrating these distinct detector types,the upper limits of the corresponding mass cross-section in dark matter detection can be lowered.We propose a phonon detector utilizing solid argon as the absorber,which combines the advantages of both aforementioned detector types.However,due to the requirement for an ultra-low temperature environment in the tens of millikelvin(mK)range,experimental investigations of solid argon phonon detector performance are currently constrained by technical limitations.Therefore,the performance analysis of the solid argon phonon detector presented in this study is only based on sapphire phonon detectors.Although there may be discrepancies between this approximation and the actual performance,the intrinsic characteristics of phonon detectors permit a qualitative evaluation of the solid argon phonon detector's potential capabilities.
