Quantum efficiency of cesium iodide photocathodes in the 120-220 nm spectral range traceable to a primary detector standard

Differently prepared CsI samples have been investigated in the 120-220 nm s pectral range for their quantum efficiency, spatial uniformity and the effe ct of radiation aging. The experiments were performed at the PTB radiometry laboratory at the Berlin synchrotron radiation facility BESSY. A calibrate d GaAsP Schottky photodiode was used as transfer detector standard to estab lish traceability to the primary detector standard, because this type of ph otodiode - unlike silicon p-on-n photodiodes - proved to be of sufficiently stable response when exposed to vacuum ultraviolet radiation. The paper re views the experimental procedures that were employed to characterize and ca librate the GaAsP photodiode and reports the results that were obtained on the investigated CsI photocathodes. (C) 1999 Elsevier Science B.V. All righ ts reserved.