LIGO Document T1800485-v6
- The purpose of this technical note is to document the frequency response of the U200 mount, and the different responses that is obtained when Viton dampers are installed in various configurations in the mount. Configurations include Viton O-Rings between the two sides of the mirror mount, pressing Viton against the springs of the mount, and pressing Viton against the springs of the mount while putting a Viton pad between the base and mirror mount. The addition of Viton against the springs of the mount reduced the amplitude of the resonance frequencies that were found in the undamped case and fully damped the resonance frequency that created by the springs of the mount at 681Hz. The configuration with Viton on the springs and a Viton pad between the base and the mirror mount damped all of the resonance frequencies by at least a factor of 10. A concern with the Viton pad is the possibility of long-term beam point drift. An experiment over 21 days revealed that the max drift in pitch was .02 degrees.
DCC Version 3.4.2, contact