Contamination and UV ageing of diffuser targets used in satellite inflight and ground reference test site calibrations

Anna Vaskuri, Claire Greenwell, Isabel Hessey, Jordan Tompkins, Emma Woolliams

Research output: Contribution to journalConference articleScientificpeer-review

1 Citation (Scopus)
87 Downloads (Pure)

Abstract

Diffuser reflectance targets are key components in in-orbit calibrations and for verifying ground reference test sites. In this work, Spectralon, Diffusil, and Heraeus diffusers were exposed to exhaust gases and ultraviolet (UV) radiation in the ambient air conditions and their degradations were monitored by measuring changes in spectral reflectances. Spectralon is a state-of-the-Art diffuser made of polytetrafluoroethylene, and Diffusil and Heraeus diffusers are made of fused silica with gas bubbles inside. Based on the contamination tests, Spectralon degrades faster than fused silica diffusers. For the samples exposed to contamination for 20 minutes, the 250 nm -400 nm total diffuse spectral reflectance of Spectralon degraded 3-5 times more when exposed to petrol-like emission and 16-23 times more when exposed to diesel-like emission, compared with Diffusil. When the reflectance changes of Spectralon were compared with those of Heraeus, Spectralon degraded 3-4 times more when exposed to petrol-like emission for 20 minutes and 5-7 times more when exposed to diesel-like emission for 7.5 minutes. When the samples contaminated were exposed to UV radiation in the ambient air, their reflectance gradually restored back to the original level. In conclusion, fused silica diffusers are more resistant to hydrocarbon contaminants present in ground reference test sites, and thus more stable under UV radiation in the air.

Original languageEnglish
Article number012001
Number of pages9
JournalJournal of Physics: Conference Series
Volume972
Issue number1
DOIs
Publication statusPublished - 2 Mar 2018
MoE publication typeA4 Article in a conference publication
EventInternational Conference on New Developments and Applications in Optical Radiometry - Tokyo, Japan
Duration: 13 Jun 201716 Jun 2017
Conference number: 13

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