Abstract: A monochromatic spectrometer for evaluating contamination changes in the surface condition of lenses, reflectors and similar optical samples in the vacuum of a space mission includes a vacuum ultraviolet beam source redirected from a dispersion grating through a test station and reflected from a mirror to a photodetector. A rotatable carrier supports two or more optical samples, both transmissive and reflective and selectively positions one sample at a time at the test station so that the selected sample modifies the VUV beam according to its surface condition. The mirror is movable from a first position in which it reflects the beam transmitted through a sample to second position in which it reflects the beam reflected from a sample. The sample condition measured by the photodetector, the position of the rotatable carrier and mission elapsed time are recorded in a memory for re-transmission or later read out.

Abstract: A shield for admitting laser beams to a target in a reaction chamber while obstructing exit of target ejected debris from the chamber is formed by coating the opposable faces of two supports with a layer of release agent and a coating protecting the release layer. A bead of transparent epoxy compound is then pressed between the two supports to form an epoxy shield. While the shield is on one support a framing holder is epoxied to the shield.

Abstract: A monochromator has three ports or slits including two entrance slits and an exit slit. A single mirror and a diffraction grating define a first, folded path between an entrance slit on one side of the housing and an exit slit on the opposite side of the housing. The mirror is movable in and out of a second path between the second entrance slit and the grating so that a second path may be completed from the second entrance slit to the grating and thence to the exit slit. Alternatively two of the ports may be used as exit slits and one as an entrance slit.