Evidence Against Carbonization of the Thin-Film Filters of the Extreme Ultraviolet Variability Experiment onboard the Solar Dynamics Observatory
Charles Tarrio, Robert F. Berg, Thomas B. Lucatorto, Andrew Jones, Frank Eparvier, Brian Templeman, Donald Woodraska, Marie Dominique
In spite of strict limits on outgassing from organic materials, some spacecraft instruments making long-term measurements of solar extreme ultraviolet (EUV) radiation still suff er signi cant degradation. While such measures have reduced the rate of degradation, they have not completely eliminated it in some cases. For example, in five years, the aluminum fi lters used in the Extreme Ultraviolet Variability Experiment (EVE) instruments onboard the Solar Dynamics Observatory (SDO) suff ered losses exceeding 40% at 30.4 nm. Comparing those losses with the negligible losses of nearby zirconium filters on the same instruments indicated that the problem was not due to carbonization on the Sun-facing side of the fi lter. To investigate whether the loss was due to carbon deposition on the downstream face of the Al lter, we exposed the backsides of Al and Zr fi lters to EUV in the presence of a volatile organic solvent in the laboratory and concluded that this could not be the cause. Given that the residual gas composition in the SDO spacecraft likely has water vapor as well as organics, these fi ndings suggest that the transmission loss in the Al filter originated with oxidation caused by UV-activated adsorbed water.
, , R.
, Lucatorto, T.
, Jones, A.
, Eparvier, F.
, Templeman, B.
, Woodraska, D.
and Dominique, M.
Evidence Against Carbonization of the Thin-Film Filters of the Extreme Ultraviolet Variability Experiment onboard the Solar Dynamics Observatory, Solar Physics, [online], https://dx.doi.org/10.1007/s11207-021-01806-4, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930743
(Accessed September 20, 2021)