Production of Deuterated Polymer Thin Films for Ion-Beam Fusion Experiments*

At ion-beam facilities such as the 1.7 MV Pelletron Accelerator and the 30 kV Duoplasmatron ion source at SUNY Geneseo, deuterated polyethylene thin films are bombarded by deuterons, producing fusion products to characterize inertial confinement fusion detection systems.  A refurbished thin films deposition system is being commissioned to produce the deuterated polymer targets via thermal evaporation.  The high vacuum system for the 18-in diameter bell jar includes a turbomolecular pump and associated valves and gauges.  Deuterated polyethylene powder is placed in a tantalum boat located in the center of the bell jar and attached to high-current feedthroughs.  Films are deposited on commercially obtained glass slides treated by a release agent and covered with 10 mg/cm² carbon films; the slides are positioned above the deuterated polymer source on an octagonal mount uniquely designed to hold the slides 8 inches from the source, normal to the incoming material, and 30 degrees from the vertical.  A rate deposition monitor is used to monitor the film thickness during deposition.  After the desired thickness is obtained, the films can be mounted on target rings using the floating technique.