DEVELOPMENT OF A PARALLEL-PLATE PROPORTIONAL COUNTER TRD WITH SUPPRESSED SENSITIVITY TO IONIZATION

The development of a parallel plate proportional counter which has a h ighly suppressed sensitivity to ionization but retains a good X-ray si gnal to noise ratio is presented. Details of the laboratory developmen t and actual beam tests showing the pi/e rejection are described. Beca use of its insensitivity to ionization this type of detector can be us eful in an environment where the number of minimum ionizing particles is high, but uninteresting; however, the detector is very sensitive to the highly localized electron cloud from converted X-rays making it i deal as a transition radiation X-ray detector. Thus, this detector onl y gives a signal for charged particles above TR threshold; all other p articles below this threshold produce no TR X-rays giving only a pedes tal-like signal. The system's potential performance for pin separation in the intended neutral hyperon experiment is evaluated.