SELF-TRIGGERED LIQUID XENON DRIFT CHAMBER BY THE USE OF PROPORTIONAL IONIZATION OR PROPORTIONAL SCINTILLATION

A liquid xenon drift chamber with an electron drift space of 13 mm in length has been constructed and the spatial resolution of the drift chamber was investigated by using alpha particles. In this experiment, the scintillation light directly produced by an alpha particle was used as trigger signal. To detect the drifted electrons, a proportional counter was used with proportional ionization or proportional scintillation mode. The best value of the spatial resolution (r.m.s.), achieved in the drift chamber, was about 20 μm for both modes. From analytical considerations it is concluded that the main part of the resolution comes from the position uncertainty caused by the finite range of alpha particles in liquid xenon and the finite size of the alpha source. This shows that, if such a drift chamber is used for minimum ionizing particles, a spatial resolution of less than ±10 μm can be expected. © 1979.