A Beam Profile Indicator with Solid State Detectors

The instrument described in this paper was built with the purpose of providing a display of the profile of secondary beams from high energy accelerators. It is capable of handling 105 particles per cm2 per machine pulse, assuming a 20 msec spill. The profile is measured by an array of 32 semiconductor detectors, 4 nm apart and arranged in the form of a cross. The detectors count the individual impinging particles. The total numbers of counts on each detector are fed continuously to a multichannel scaler, which in turn delivers an analogue live display and a digital printout. Details of the electronics and methods of fabrication of the detectors, as well as their problems, are discussed.