Scintillation properties and luminescence response of the ZnWO4 crystal to γ and proton beams

We investigated the scintillation properties, including the energy resolution, the pulse height spectrum, and the decay time, of ZnWO4 (ZWO) crystals by using a 661-keV γ-ray source and proton beams with various energies. The luminescence response of the ZWO crystal to the energy of the proton beam was measured with proton beam energies in the range from 20 MeV to 35 MeV by using the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS) with aluminum degraders of different thicknesses. We also measured the proton luminescence spectrum of the ZWO crystal. For the determination of the proton-beam energy incident on the crystal after it had passed through the degrader and 270 cm of air, we used a Monte Carlo simulation based on the Geant4 code. We calculated the differential stopping power, dE/dr, of the ZWO crystal for the available proton beam energy by using a simulation with the SRIM code. Using these simulated and the experimental results, we calculated the Birks parameter, kB, of the semi-empirical Birks law, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{{dL}} {{dr}} = \frac{{A\frac{{dE}} {{dr}}}} {{1 + kB\frac{{dE}} {{dr}}}}$$\end{document}.