Photoluminescence and optical transmission of diffusion-pump oils.
The photoluminescence and optical transmission of the four widely used diffusion-pump oils, DC-705, DC-704, Convalex-10, and Convoil-20, were measured. Each of the oils was found to be transparent throughout the visible region, showed some absorption in the near uv region, and became very opaque below approximately 300 nm. Both Convalex-10 and Convoil-20 turned yellow after exposure to uv light. No such change was noted in DC-705 or DC-704. Photoluminescence was produced in each of the four oils when irradiated with uv light. Both DC-705 and DC-704 had a nearly identical luminescence spectra that peaked at 350 nm. The spectra of Convalex-10 and Convoil-20 were fairly complex, with several peaks in the visible region.
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