Vibration properties of mirror foils for hard x-ray telescope onboard satellite

ABSTRACT ASTRO-H is a next version of Japanese X-ray astronomy sate llite for lunch in 2014. The hard X-ray telescope (HXT) on board the satellite has a cylindrical mirror housing which contains reflection circular mirror foils. In the present paper, vibration properties of the mirror foils installed in the HXT on-board a satellite were investigated. Vibration tests and FEM analysis of mirror foils installed in the part model of HXT were conducted. From the experimental results, it appeared that the mirror had resonant frequencies at 64, 73 and 118Hz. The modal shapes of 64 and 73Hz peaks showed that the maximum amplitude appeared at edges of the foil. On the other hand, vibration amplitude became maximum at the center in the modal shape of 118Hz peak. In addition, it appeared that the first peak of the edge mode decreased with increasing acceleration while the second peak had weak dependency on acceleration. These vibration behaviors are thought to be governed degree of constraint of the connections between the foil and alignment bars. Keywords: Hard X-ray telescope, Satellite, Vibra tion, Mirror foil, Modal analysis