Crystal Surface Treatment 1: Polished CsI Crystal wrapped in 3 teflon layers, front face covered with black paper, entire crystal wrapped in one layer of Mylar. Crystal Surface Treatment 2: same as 1 but Crystal Surfaces are Painted with Ukraenian Wavelength-shifting Lacquer Crystal Surface Treatment 3: Crystal surfaces are painted with Ukraenian Wavelength-shifting lacquer, and entire crystal is wrapped in one layer of Mylar