The use of near normal incidence diffraction
gratings in the 300 to 280 Angstrom wavelength range placed severe demands on the
gratings' surface cleanliness at the molecular level. In addition, the need for low scatter high
reflectivty surfaces for the grazing incidence components placed demands on both molecular
and particulate cleanliness. The entire instrument assembly and test took place
in class 100 clean rooms. Mounted into the optical bench are two quartz crystal microbalances
(QCM). These are used in flight to continue contamination monitoring. The inflight data acquired since launch are shown here:
Last revised on .