Alpha-Particle Scintillations in Organic Compounds

Abstract

THE papers^1–7 previously published on organic luminescent materials do not enable a direct and reliable comparison of their conversion efficiencies (conversion of incident radiation energy into light energy) to be made. This is so because different types of photomultipliers have been used and not all the compounds have been investigated with similar radiation. Further, the results reported are not consistent. Most of the materials previously used have been re-investigated in this laboratory under the same conditions in each case and their efficiencies as scintillation counters assessed. The effective use of a fluorescent material depends on the spectral response of the photomultiplier and on the wavelength of the light emitted when a scintillation takes place. The results presented are therefore of additional interest, as RCA 931 type photomultipliers were used to obtain the major part of the information available in the literature, whereas the results given here were obtained with an EMI 5311 photomultiplier which has a different response. In addition, materials not so far reported on have been investigated.