Luminescence of Polymethyl Methacrylate Excited by a Runaway Electron Beam and by a KrCl Excilamp

This paper reports an experimental study of luminescence excited in polymethyl methacrylate (PMMA) by a runaway electron beam and by a KrCl excilamp with a wavelength of 222 nm. It is shown that the major contributor to the luminescence of PMMA in both cases is a luminescence band with a maximum intensity at 490 nm. Based on experiments with the excilamp, it is supposed that Cherenkov radiation with a wavelength shorter than 300 nm is bound to increase the intensity of this band. The luminescence intensity at 490 nm varies proportionally with the number of beam electrons, allowing the use of this radiation to determine the number of high-energy electrons in electron beams. In PMMA with high absorption at 300-400 nm, one more luminescence band with a maximum intensity at 400 nm is observed. It is confirmed that in gas diodes at a pressure of 760 torr, the intensity of Cherenkov radiation against the background of luminescence is low and undetectable.