The Study Of The Effect Of Cosmic Ray Activation Germanium Crystal On The Detector

In recent years, to detect dark matter has become one of the most cutting-edge issues incosmology and physics, and it will be the most popular study. Detection of dark matter willmake us much closer to understanding the structure and the formation process of the universe.It can be foreseen that the detecting of dark matter will be very meaningful. Among manypredicted theoretical models, weakly interacting particles (WIMPs) are considered to be themost important candidates.In virtue of the excellent natural conditions in Sichuan Jinpingshan China, the first verydeep basement is built, which is the China Jinping Underground Laboratory (CJPL). It givesthe Chinese laboratories the most favorable conditions of very low background experimentsthat the vertical depth of2400meters is rock covered, thus, the low background experimentsbegin. The background of cosmic rays and their secondary particles can be effectivelyshielded by the very thick rock layers as well as the shield inside laboratory. But thebackground of cosmic rays activate detector material in sea level will become a serious hazardof such experiments, because it is in the most center of the laboratory, which makes itimpossible to be effectively shielded. What is more, the effect of radioactive of experimentalmaterial itself to the detectors cannot be ignored.High-purity germanium (86%76Ge and14%74Ge) will be exposed to cosmic rays for along time during the manufacturing and shipping process. During these processes, thephenomenon of cosmic ray activation will produce large amounts of radioactive elements inhigh-purity germanium crystal. Because HPGe is most frequently used in ultra-lowradioactive background experimental, its activation impact cannot be ignored. Thus, thepurpose of my research is to estimate the effect of cosmic ray activation of purity germaniumcrystal on the radioactive detector itself. In this article, according to the known produce ofactivation purity germanium crystals, the background of the activation of the germaniumcrystal within itself-rays as well as X-ray in0~12keV is estimated. The results can bereferred to remove the laboratory background.