Development of a parallel plate proportional counter TRD with suppressed sensitivity to ionization

The development of a parallel plate proportional counter which has a highly suppressed sensitivity to ionization but retains a good X-ray signal to noise ratio is presented. Details of the laboratory development and actual beam tests showing the πe rejection are described. Because of its insensitivity to ionization this type of detector can be useful 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 ideal as a transition radiation X-ray detector. Thus, this detector only gives a signal for charged particles above TR threshold; all other particles below this threshold produce no TR X-rays giving only a pedestal-like signal. The systemʹs potential performance for pπ separation in the intended neutral hyperon experiment is evaluated.