Thin synthetic windows for cryogenic targets

A liquid hydrogen/deuterium target with very thin windows made out of synthetic foils is described. The target has been used for nuclear physics experiments in medium-energy proton and alpha beams. Thin foils have been selected to allow low-energy particles to get out of the target and to have very little background from target-window material. The foils have been tested under different pressures and temperatures. The permeability of some of the foils was monitored with these variations. The foils were also tested for radiation resistance by placing them in the beam.