Determination of Detection Efficiencies of CsI Photodiode and Microchannel Plate Detectors

Abstract

We have measured the detection efficiencies of a CsI photodiode (Si02 windowed) and a microchannel plate detector (MCP) with an opaque CsI photocathode at 1850 A. Also, a detection efficiency curve was measured for a windowless CsI photodiode in the 1000 - 1700 A wavelength range. The efficiency for the MCP was measured in the pulse counting mode. Efficiencies for the windowed CsI photodiode and MCP at 1850 A were 9.04% and 19.1% respectively. The efficiency curve for the windowless CsI photodiode was comparable to the typical curve found for CsI-coated photocathodes. Finally, the pulse height distribution was measured for the MCP configuration and yielded good full width at half maximum (FWHM) values of 62.2% at 4.8 kV and 97.3% at 4.6 kV.