A Cerenkov detector for the energy calibration of electron beams from 9-22 MeV

Abstract

A new way of estimating the energy of electron beams has been developed using Cerenkov radiation generated by relativistic electrons passing through different gases. Recently, the authors have been studying this method using three different gases, pentane, CO2 and air which have threshold values of 9.0, 17.0, 22 MeV respectively at STP. The detector consists of a 120 cm long gas filled pipe with a thin brass window at the front; a mirror set at 45 degrees to the beam direction at the far end reflecs the Cerenkov radiation onto the cathode of a photomultiplier tube. This work was done primarily with a 32 MeV linear accelerator for which it was difficult to vary the energy continuously and a comparison with an 18 MeV betatron was made using activation analysis and range relationship methods.