Towards a first design of a Newtonian-noise cancellation system for Advanced LIGO

TL;DR

This paper proposes an initial design for a Newtonian-noise cancellation system for Advanced LIGO, utilizing optimized seismometer arrays based on seismic models to reduce low-frequency gravitational noise.

Contribution

It introduces a simplified seismic array design for Newtonian-noise mitigation at LIGO, demonstrating feasibility with seismic observations and models.

Findings

Seismic models fit observational data well

Seismometer self-noise limits noise reduction

Monitoring surface displacement inside buildings may suffice

Abstract

Newtonian gravitational noise from seismic fields is predicted to be a limiting noise source at low frequency for second generation gravitational-wave detectors. Mitigation of this noise will be achieved by Wiener filtering using arrays of seismometers deployed in the vicinity of all test masses. In this work, we present optimized configurations of seismometer arrays using a variety of simplified models of the seismic field based on seismic observations at LIGO Hanford. The model that best fits the seismic measurements leads to noise reduction limited predominantly by seismometer self-noise. A first simplified design of seismic arrays for Newtonian-noise cancellation at the LIGO sites is presented, which suggests that it will be sufficient to monitor surface displacement inside the buildings.