Design of a fast compton spectrometer for measuring megavoltage bremsstrahlung spectra

Measurements of bremsstrahlung X-ray spectra produced by high energy electron linacs (such as those found in many cancer therapy centers) pose special problems. These machines typically operate at very low duty factors, have very high photon fluences, and produce X-rays of energy too high to be measured accurately with a single detector. A compton pair spectrometer utilizing fast plastic scintillators and nanosecond timing techniques suitable for these measurements is described.