High-Temperature Performance of Metal-Ceramic Photomultipliers

The feasibility of making metal-ceramic photomultipliers capable of surviving and operating at temperatures up to 175°C has been demonstrated. These tubes use the CsK2Sb photocathode and have typical quantum efficiencies of 25 to 30 per cent. Results indicate that CsK2Sb is an extremely stable photocathode when a suitable environment can be provided. Tube performance characteristics have been measured over the temperature range from room temperature to +175°C. The variation of sensitivity (pulse height) and pulse-height resolution as a function of temperature has been determined. The temperature dependence of dark current and noise has also been evaluated. The data indicate that tubes of this type are suitable for many scintillation counting applications throughout this temperature range.