Recent developments in photodetectors for use in severe environments

Several new types of photodetector have been developed for use in severe environmental conditions; four types of phototube are especially designed to be operated in high magnetic fields of several kilogauss or more. A photomultiplier which is designed for use under pressures as high as 600 atm has stable gain and energy resolution under such high pressures. And a 15 inch diameter spherical photocathode photomultiplier has also been developed for high pressure use when packed in a special strong glass housing. There is another photomultiplier which can be operated in temperatures over 175°C, such as in oil well logging works.