Electrically charged particle beam measurement - using rotary disc collimator masking a concentric bank of annular radiation detectors each associated with respective excitation monitors

摘要

Focal irradiation by a beam of electrically charged particles, is measured by a device having a rotating disc type collimator (40). Along one radius of the disc (40) a number of apertures (41 to 44) define a composite rotating aperture through which the beam passes prior to incidence upon banks of radiation detector (11 to 14). The detectors are annular in form and lie beneath respective ones of the trajectories of the rotating apertures. The detectors are concentrically disposed, and coaxial with the rotary disc collimator. A bank of four meters monitor excitations in the annular detectors so that the beam characteristics may be obtained.