Design and sensitivity of a 6-axis seismometer for gravitational wave observatories

TL;DR

This paper introduces a highly sensitive 6-axis seismometer with a novel control system, designed to enhance gravitational wave detection and fundamental physics experiments by surpassing existing commercial sensors in sensitivity.

Contribution

The paper presents a new 6-axis seismometer design with a custom control system and interferometric readout, achieving over ten times the sensitivity of commercial sensors for angular measurements.

Findings

Achieved over an order of magnitude improvement in angular sensitivity.

Developed a control system suitable for gravitational-wave observatories.

Demonstrated potential applications in fundamental physics experiments.

Abstract

We present the design, control system, and noise analysis of a 6-axis seismometer comprising a mass suspended by a single fused silica fibre. We utilise custom-made, compact Michelson interferometers for the readout of the mass motion relative to the table and successfully overcome the sensitivity of existing commercial seismometers by over an order of magnitude in the angular degrees of freedom. We develop the sensor for gravitational-wave observatories, such as LIGO, Virgo, and KAGRA, to help them observe intermediate-mass black holes, increase their duty cycle, and improve localisation of sources. Our control system and its achieved sensitivity makes the sensor suitable for other fundamental physics experiments, such as tests of semiclassical gravity, searches for bosonic dark matter, and studies of the Casimir force.