Related Issues Of Scintillator For The Detection Of Dark Matter Research

It’s very significant to search WIMP (Weakly Interacting Massive Particle)which is the best candidates of Dark Matter. But the probability of interaction ofWIMP with ordinary matter is very low. So it is the key to choose the core detectormaterial to enhance excluding the background and improve the signal resolution. Thematerials are used to directly detect WIMP particle, including Xenon, CsI (Tl) crystal,NaI (Tl) crystal and semiconductor. The research have been done to compare andanalyze the performance of CsI (Na) crystal and BaF2crystal, in order to select thebest core dark matter detector materials.In this paper, basing on the result of CsI (Na) crystal, the crystal of BaF2pulseshape discrimination recoil signal and electric signal performance experiments werecarried out, experimental results show that the emission was the strongest BaF2crystal-40℃. Relative to normal temperature, nuclear recoil luminescence increased76%,electron recoil luminescence increased61%.At this temperature, the removal efficiency of background were96.5±3%and99.6±0.7%, respectively, the integral method and the average time method with60%detection efficiency. Therefore the particle identification capability of BaF2crystal isworse than CsI (Na) crystal.In order to use the Geant4simulation to acquire the waveforms of nuclear recoilsignal and electron recoil signal, which is most close to the result of experimental test, it was investigated that the optical parameters of CsI (Na) crystal. By setting theseparameters in Geant4program, the simulation waveform and the experimentalwaveform coincides well. This is the fundamental for the realization of to get theperformance of discrimination particles of the dark matter detector by simulating.The natural radionuclides238U,232Th and40K of dark matter detector itself andshielding material were researched basing on Geant4simulation. The results of thisstudy to evaluate the performance of the dark matter detector and provide referencefor optimizing detector design.