A Rotatable Substrate Mount for Thin Film Evaporation*

A rotatable substrate mounting system has been developed for the Thin Film Evaporator at SUNY Geneseo so that multiple sides of a substrate can be coated without breaking vacuum to reposition the substrate. To support the iSNAP experiment carried out at MTW laser at the Laboratory for Laser Energetics (LLE) at the University of Rochester, plastic scintillator detectors were coated with 200 nm-thick aluminum films to absorb visible light while allowing the passage of energetic protons and deuterons. To coat each side of the scintillator, the vacuum system needed to be vented, the sample repositioned, and then the system pumped down again, resulting in an inefficient and time-consuming process. The new substrate mount allows one to change which side is coated without opening the bell jar. The substrate is mounted above the evaporation source on a rod attached to a sprocket driven by a chain connected to a rotatable vacuum feedthrough that is adjusted manually. Initial tests demonstrate that the new system can be used to evaporate multiple faces on a substrate, as designed.