Optical properties of plastic scintillators coated with copper, aluminum and silver by magnetron sputtering

Copper, aluminum, and silver thin films are fabricated on plastic scintillators by magnetron sputtering to improve the optical properties. The film morphology is measured by contact mode atomic force microscopy. The optical properties are determined by UV/visible spectrophotometry as well as a single-particle microbeam with proton energy of 2 MeV. Our theoretical analysis suggests a 10.28% increase in the collection efficiency compared to the uncoated plastic scintillator. The improvement in the optical properties is investigated experimentally and the Monte Carlo program SRIM 2008 is employed to investigate the influence of the metal film thickness on the ion stopping and scattering in the materials. Our study suggests that deposition of thin reflecting Cu, Al, and Ag films improves the energy and space resolution of scintillator-based particle spectrometers.