Performance of TMS and TMG for particle detector

We present the results of an extensive study of the response of TMS and TMG for particle detector application. The energy resolutions of 976 keV conversion electrons from a /sup 207/Bi source are measured in a gridded ionization chamber filled with TMS (tetramethylsilane) and TMG (tetramethylgermanium), and are found to be about 5.7 and 5.5% (rms), respectively. We also deduce a simple method of estimating the electron lifetime using a gridded ionization chamber. The free-ion yield and electron lifetime for these liquids are estimated by this simple method to be 2.64, 2.78 and 16.89 /spl mu/s, 15.40 /spl mu/s, respectively. The radiation damage of both liquids is examined by measuring the electron lifetime as a function of accumulated radiation dose in a parallel plate ionization chamber. The electron lifetime for the damaged liquid almost recovers to its initial value after repeating the purification. Also, we present preliminary results of the investigation of recombination light from a /sup 241/Am source in TMG, which directly affects the charge collection for the ionization.