A fifty-fold improvement of thermal noise limited inertial sensitivity by operating at cryogenic temperatures

TL;DR

This paper introduces a cryogenic accelerometer with unprecedented sensitivity, achieving over fifty times better thermal noise limited inertial sensitivity than previous sensors, with broad applications in gravitational wave detection and geophysics.

Contribution

The paper presents a vacuum compatible cryogenic accelerometer reaching sub-picog acceleration sensitivity from 1 mHz to 10 Hz, surpassing existing motion sensors by over three orders of magnitude.

Findings

Achieves <0.5 p$g$ Hz$^{-1/2}$ sensitivity from 1 mHz to 10 Hz.

Displacement sensitivity of <2 fm Hz$^{-1/2}$ between 2-100 Hz.

Surpasses previous sensors by more than three orders of magnitude at 1 Hz.

Abstract

A vacuum compatible cryogenic accelerometer is presented which will reach $<0.5$ p$g$ Hz$^{-1/2}$ sensitivity from 1 mHz to 10 Hz with a maximum sensitivity of 10 f$g$ Hz$^{-1/2}$ around 10 Hz. This figure can be translated to a displacement sensitivity $<2$ fm Hz$^{-1/2}$ between 2 - 100~Hz. This will supersede the best obtained sensitivity of any motion sensor by more than three orders of magnitude at 1~Hz. The improvement is of interest to the fields of gravitational wave instrumentation, geophysics, accelerator physics and gravitation. In current particle accelerators and proposed future gravitational wave detectors $<$10 K cryogenics are applied to the test masses in order to reduce thermal noise. This concept can benefit from the already present superconducting regime temperatures and reach a $>10^5$ signal-to-noise ratio of all terrestrial seismic spectra. The sensor may be used for control of beam-focusing cryogenic electromagnets in particle accelerators, cryogenic inertial sensing for future gravitational wave detectors and other fields.