Neutron-gamma discrimination of CsI(Na) crystals for dark matter   searches
  The luminescent properties of CsI(Na) crystals are studied in this report. By using a TDS3054C oscilloscope with a sampling frequency of 5 GS/s, we find out that nuclear recoil signals are dominated by very fast light pulse with a decay time of ~20 ns, while {\gamma}-ray signals have a decay time of ~600 ns. The wavelength of nuclear recoil and {\gamma}-ray signals are also different. The study of n/{\gamma} separation shows that the rejection factor can reach an order of 10-7 with signal efficiency more than 80% at an equivalent electron recoil energy of 20 keV or more. Such a property makes CsI(Na) an ideal candidate for dark matter searches. 
Xilei Sun, Junguang Lu, Tao Hu, Li Zhou, Jun Cao, Yifang Wang, Liang   Zhan, Boxiang Yu, Xiao Cai, Jian Fang, Yuguang Xie, Z...
physics.ins-det astro-ph.CO astro-ph.IM hep-ex