New Phototubes and Photomultipliers Resistive against High Magnetic Fields

The energy of particles in recent high energy physics experiments has been increasing, so that detector apparatus is inevitably placed in high magnetic field environment. Therefore new photodetectors are required which, unlike conventional photomultipliers, are inherently insensitive to high magnetic fields. We have developed four types of new photodetector for the use in high magnetic fields: a one-atm. xenon filled phototube, a rectangular vacuum photodiode, a one-stage photomultiplier and a photomultiplier with fine-mesh dynodes. Each of them is specially designed on the basis of the analysis of the behavior of electrons in electromagnetic fields and is capable of stable operation in magnetic fields as high as several kilogauss or more.