Study of optical dumpers used in high vacuum system of interferometric gravitational wave detectors

Abstract

Outgassing velocities and optical absorption coefficients of black colored optical absorbers (UB-NiP, Phosblack II, Raydent, ECB+DLC and Alumite) were studied to reduce scattered and strayed light in interferometric gravitational wave detectors. The measured results showed that the UB-NiP had the largest optical absorption coefficient of 99.89% for 1064nm wavelength of light. For the outgassing velocity, the ECB+DLC had the lowest value, which was 1 × 10-8 Pam3/s/m2 at 20 hours. This value was about two orders of magnitude smaller than that of the UB-NiP, however, its optical absorption coefficient was only 65 %. Therefore, we concluded that the UB-NiP is suitable as an optical dumper with small area and high efficiency, and the ECB+DLC is suitable as large area coating such as a use for vacuum chamber walls. © 2006 IOP Publishing Ltd.