Scintillation yield and scintillation time dependence in gaseous Argon with different purities

Liquefied noble gases as detection media for WIMPs are widely used by a number of existing and proposed experiments. To investigate the characteristics of LAr detector, a LAr test facility was designed and manufactured in Tsinghua University. The study of the scintillation yield and the scintillation time constants showed that the scintillation yield strongly depends on the Argon purity, and the slow component is also very sensitive to the impurities. So it´s necessary to utilize a liquid Argon re-circulation system while running. Additionally, the Argon purity can be monitored by measuring the change of the scintillation yield and the Argon scintillation slow component with time.