Additional Vibration Isolation

The Passive Vibration Damping Frame (PVD) consists of a heavy-duty frame and weight (~200 kg machined aluminum plate) added to the top flange. The Pulse Tube Cryocooler motor is placed on a shelf attached to the main frame. The added mass helps absorb vibrations that couple through the floor (connecting the frames) and thermal links (copper braids) between the cold head and cryostat flanges (4K and 50K Flanges).

The PVD Frame can be upgraded to the Active Vibration Damping Frame (AVD) which includes an active damping system. When active damping is enabled, there is an active motor correcting the relative movement between the frame and the top plate of the cryostat. This damping also corrects for tilt and rotation between 1 Hz and 120 Hz.

Note that since the AVD Frame is an upgraded version of the PVD Frame, the latter is a prerequisite for AVD Frame installation.

Another vibration reduction upgrade is to include an additional frame with pump lines molded into a concrete block, with still-pumping lines further decoupled through 2 metallic T-damper pipes.

This reduces vibrations that couple through the cryostat from the Gas Handling System (GHS) and the various pump lines.