IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Friday Sessions
       Session VST-FrM

Paper VST-FrM8
Direct Measurement of Residual Gas Effect on the Sensitivity in TAMA300

Friday, November 2, 2001, 10:40 am, Room 132

Session: Accelerators Technology, Fusion Machines & Gravitational Wave Detectors
Presenter: R. Takahashi, National Astronomical Observatory of Japan
Authors: R. Takahashi, National Astronomical Observatory of Japan
Y. Saito, High Energy Accelerator Research Organization, Japan
M. Ando, The University of Tokyo, Japan
K. Arai, National Astronomical Observatory of Japan
M. Fukushima, National Astronomical Observatory of Japan
G. Heinzel, National Astronomical Observatory of Japan
S. Kawamura, National Astronomical Observatory of Japan
D. Tatsumi, National Astronomical Observatory of Japan
T. Yamazaki, National Astronomical Observatory of Japan
S. Moriwaki, The University of Tokyo, Japan
Correspondent: Click to Email
A laser interferometer gravitational wave detector requires an ultra-high vacuum in the ducts which the laser beams pass through. TAMA300, involving two 300 m-long vacuum ducts, is kept in 2x10@super -6@ Pa of vacuum pressure so as to reduce scattering-effects due to residual gas molecules. The sensitivity attained so far is 2x10@super -18@ m/rtHz around 1 kHz. By introducing a Xe-gas into the entire system of TAMA300, we directly observed the residual-gas effect on the sensitivity. It is found that the Xe-gas pressure of 6x10@super -2@ Pa induces an increase in the mirror displacement noise of 3x10@super -18@ m/rtHz. This noise level is consistent with a calculated optical fluctuation of the laser beam due to residual-gas scattering.