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Experiment Title: Thin Metal Film and Multilayers Experiments

Original Principal Investigator(s): Delaboudiniere, Dr. Jean Pierre - Invest. Role: Original, Carabetian, Dr. C. - Invest. Role: Present, Delaboudiniere, Dr. Jean Pierre - Invest. Role: Present, Hochedez, Dr. J.F. - Invest. Role: Present, Berset, J.M. - Invest. Role: Original,

It is well known that ultraviolet (UV) and extreme ultraviolet (EUV) experiments suffer degradation during space missions of even 1 month duration. It is believed that the degradation is due mainly to condensation of outgassing products, followed by solar-induced polymerization. However, penetrating charged particles are also known to produce volume effects. On the other hand, degradation may start immediately after manufacturing of the component due to oxidation, moisture, or chemical corrosion by atmospheric constituents such as CO2 and SO2. Finally, when the filters are used as windows for gas absorption cells or gas filters, or when they define the instrumental bandwidth by themselves (as in photometers and colorimeters), the effects of mechanical degradation by thermal cycling and/or dust impact may be dramatic.

In preparation for the SOHO mission planned by NASA/ESA for launch in 1995, test samples of optical components to be used by the Extreme Ultraviolet Imaging Telescope were placed on LDEF. These components included thin film filters used for visible light rejection, and a new type of optical reflectors developed for the EUV since 1975. These reflectors consisted of a periodic stack of multilayered thin films, deposited on glass substrates. They operated by building up reflectivity from constructive interference of individual beams reflected at the interface between successive highly and weakly absorbing materials. The layer thicknesses are a fraction of the wavelength of the light beam reflected so that the period of the structure is lambda/2 (lambda being the operating wavelength). samples of such mirrors were located on the LDEF in order to evaluate the effect of thermal cycling, and surface contamination in low Earth orbit.

Photograph Classification: None

Associated Photograph(s):
LaRC - None
KSC - None
JSC - None

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