Gaseous Delta-e-type Phoswiches

Results are presented on the use of gaseous xenon as the DELTA-E stage of a phoswich scintillator detector. The timing characteristics of the xenon detector have been investigated and found to be suitable as either the fast or the slow component of a phoswich detector depending on the operating pressure of the xenon. A xenon-CsI(Tl) and a xenon-plastic phoswich have been built and tested. The xenon-plastic detector is expected to be more suitable for high energies. In addition to the ease of obtaining various thicknesses by adjusting the pressure, the excellent uniformity of a gaseous DELTA-E can provide an improved identification of heavy ions.