Development of gaseous tracking devices for the search of WIMPs

The Time Projection Chamber (TPC) has been recognized as a potentially powerful detector for the search of WIMPs by measuring the directions of nuclear recoils, in which the most convincing signature of WIMPs, caused by the Earth's motion around the Galaxy, appears.We report on the first results of a performance study of the neutron exposure of our prototype micro-TPC with Ar–C2H6Ar–C2H6 (90:10) and CF4CF4 gas at 150 Torr.