暗物质是当今物理学最基本也是最吸引人的前沿研究课题之一,对认识宇宙起源、演变和结构以及物质的本源等基本科学问题具有十分重要的意义.暗物质的理论研究和实验探测经过几十年的积累和发展已经取得了长远的进步.实验上有多种方法可...暗物质是当今物理学最基本也是最吸引人的前沿研究课题之一,对认识宇宙起源、演变和结构以及物质的本源等基本科学问题具有十分重要的意义.暗物质的理论研究和实验探测经过几十年的积累和发展已经取得了长远的进步.实验上有多种方法可以进行暗物质粒子的探测,直接探测是一种非常重要的手段.本文评述了暗物质直接探测方法的原理和当今国际国内采用直接探测法的不同实验的研究现状,着重介绍了中国暗物质实验(China Dark matter Experiment,CDEX)合作组的研究历程、探测技术和数据分析方法、以及研究取得的重要成果和未来规划.展开更多
A 994 g mass p-type PCGe detector has been deployed during the first phase of the China Dark matter EXperiment, aiming at direct searches for light weakly interacting massive particles. Measuring the thickness of the ...A 994 g mass p-type PCGe detector has been deployed during the first phase of the China Dark matter EXperiment, aiming at direct searches for light weakly interacting massive particles. Measuring the thickness of the dead layer of a p-type germanium detector is an issue of major importance since it determines the fiducial mass of the detector. This work reports a method using an uncollimated ^133Ba source to determine the dead layer thickness. The experimental design, data analysis and Monte Carlo simulation processes, as well as the statistical and systematic uncertainties are described. A dead layer thickness of 1.02 mm was obtained based on a comparison between the experimental data and the simulated results.展开更多
We report results of a search for light weakly interacting massive particle（WIMP） dark matter from the CDEX-1 experiment at the China Jinping Underground Laboratory（CJPL）. Constraints on WIMP-nucleon spin-independ...We report results of a search for light weakly interacting massive particle（WIMP） dark matter from the CDEX-1 experiment at the China Jinping Underground Laboratory（CJPL）. Constraints on WIMP-nucleon spin-independent（SI） and spin-dependent（SD） couplings are derived with a physics threshold of 160 eVee, from an exposure of 737.1 kg-days. The SI and SD limits extend the lower reach of light WIMPs to 2 GeV and improve over our earlier bounds at WIMP mass less than 6 GeV.展开更多
The CDEX-10 experiment searches for light weakly interacting massive particles, a form of dark matter, at the China Jinping Underground Laboratory, where approximately 10 kg of germanium detectors are arranged in an a...The CDEX-10 experiment searches for light weakly interacting massive particles, a form of dark matter, at the China Jinping Underground Laboratory, where approximately 10 kg of germanium detectors are arranged in an array and immersed in liquid nitrogen. Herein, we report on the experimental apparatus, detector characterization, and spectrum analysis of one prototype detector. Owing to the higher rise-time resolution of the CDEX-10 prototype detector as compared with CDEX-1 B, we identified the origin of an observed category of extremely fast events. For data analysis of the CDEX-10 prototype detector, we introduced and applied an improved bulk/surface event discrimination method. The results of the new method were compared to those of the CDEX-1 B spectrum. Both sets of results showed good consistency in the 0-12 ke Vee energy range, except for the 8.0 keV K-shell X-ray peak from the external copper.展开更多
文摘暗物质是当今物理学最基本也是最吸引人的前沿研究课题之一,对认识宇宙起源、演变和结构以及物质的本源等基本科学问题具有十分重要的意义.暗物质的理论研究和实验探测经过几十年的积累和发展已经取得了长远的进步.实验上有多种方法可以进行暗物质粒子的探测,直接探测是一种非常重要的手段.本文评述了暗物质直接探测方法的原理和当今国际国内采用直接探测法的不同实验的研究现状,着重介绍了中国暗物质实验(China Dark matter Experiment,CDEX)合作组的研究历程、探测技术和数据分析方法、以及研究取得的重要成果和未来规划.
基金Supported by National Natural Science Foundation of China(10935005,10945002,11275107,11175099)
文摘A 994 g mass p-type PCGe detector has been deployed during the first phase of the China Dark matter EXperiment, aiming at direct searches for light weakly interacting massive particles. Measuring the thickness of the dead layer of a p-type germanium detector is an issue of major importance since it determines the fiducial mass of the detector. This work reports a method using an uncollimated ^133Ba source to determine the dead layer thickness. The experimental design, data analysis and Monte Carlo simulation processes, as well as the statistical and systematic uncertainties are described. A dead layer thickness of 1.02 mm was obtained based on a comparison between the experimental data and the simulated results.
基金Supported by the National Key Research and Development Program of China(2017YFA0402200,2017YFA0402201)the National Natural Science Foundation of China(11175099,11275107,11475117,11475099,11475092,11675088)+2 种基金the National Basic Research Program of China(973 Program)(2010CB833006)support of grants from the Tsinghua University Initiative Scientific Research Program(20121088494,20151080354)the Academia Sinica Investigator Award 2011-15,contracts 103-2112-M-001-024 and104-2112-M-001-038-MY3 from the Ministry of Science and Technology of Taiwan
文摘We report results of a search for light weakly interacting massive particle（WIMP） dark matter from the CDEX-1 experiment at the China Jinping Underground Laboratory（CJPL）. Constraints on WIMP-nucleon spin-independent（SI） and spin-dependent（SD） couplings are derived with a physics threshold of 160 eVee, from an exposure of 737.1 kg-days. The SI and SD limits extend the lower reach of light WIMPs to 2 GeV and improve over our earlier bounds at WIMP mass less than 6 GeV.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0402201)the National Natural Science Foundation of China(Grant Nos.11475092,11475099,11675088,and 11725522)
文摘The CDEX-10 experiment searches for light weakly interacting massive particles, a form of dark matter, at the China Jinping Underground Laboratory, where approximately 10 kg of germanium detectors are arranged in an array and immersed in liquid nitrogen. Herein, we report on the experimental apparatus, detector characterization, and spectrum analysis of one prototype detector. Owing to the higher rise-time resolution of the CDEX-10 prototype detector as compared with CDEX-1 B, we identified the origin of an observed category of extremely fast events. For data analysis of the CDEX-10 prototype detector, we introduced and applied an improved bulk/surface event discrimination method. The results of the new method were compared to those of the CDEX-1 B spectrum. Both sets of results showed good consistency in the 0-12 ke Vee energy range, except for the 8.0 keV K-shell X-ray peak from the external copper.
