Instrument Cryocooler Vibration Mitigation

Project Goal: Create a functioning lab mockup of the cryocooler and mounting system currently installed on the spectrograph LUCI instruments of the University of Arizona Large Binocular Telescope Observatory.

The Large Binocular Telescope Observatory, or LBTO, is affected by vibrations from the cryocoolers on the spectrograph LBT Utility Camera in Infrared instruments, or LUCI. A test bed consisting of a working analogue of the cryocooler and the surrounding spring system would help reveal possible improvements that can be made to reduce the vibrations.

The Vibration Mitigation System has several subsystems that imitate the conditions of the actual LUCI design by supporting a cryocooler with a spring holding system and mounting it to an optical breadboard that is connected to an artificial loading system. The current LBTO structure was slightly modified to fit the test device and to compensate for the lack of force caused from the vacuum of the LUCI instruments. The vibration spectrum of the mockup was measured and modified until it was as close to the spectrum of the cryocoolers in the LBTO as possible.

Experiments with this lab mockup can test improvements to the springs and cryocooler to reduce transmitted vibrations to the telescope.