X-ray detection with a scintillating YAP-window hybrid photomultiplier tube

A YAP(YAIO(3): Ce)-scintillating window, coated on its inner surface with a n S20-photocathode, seals a cross-focusing hybrid photomultiplier tube (HPM T) equipped with a small p-i-n anode of 2-mm diameter, This new radiation d etector separates S-ray lines down to about 2-keV peak energy from the HPMT noise. Its detection efficiency for high gamma energies depends on the YAP -window thickness and amounts to about 18% attenuation at 400-keV energy in the present version, Competitive radiation detectors like silicon photodio des and silicon drift chambers are discussed and compared to our prototype, with particular attention given to their energy resolution and noise perfo rmance, which limits their active area considerably.