Low-vibration cryogenic testbed for inertial sensor characterization

Sub-picometer-class, cryogenic inertial sensors are developed to monitor suspension stages near the mirror of future gravitational-wave detectors, which operates in extremely low vibration and cryogenic environments. We present a testbed to validate their performance before deployment, that provides a 4 K, low-vibrating environment. The vibrating parts of a closed-cycle pulse-tube cryocooler are passively decoupled from the
testing environment with a convective pocket of gaseous Helium and soft thermal links. The setup is placed on a 6 degrees-of-freedom actively isolated platform to mitigate seismic motion disturbances. The 4 K testing environment will reach a sub-nm/√Hz vibration level from 1 Hz.