Joint Optimization of seismometer arrays for the cancellation of Newtonian noise from seismic body waves in the Einstein Telescope

TL;DR

This paper investigates optimal placement of seismic sensors in the Einstein Telescope to maximize Newtonian noise cancellation, considering multiple test masses and seismic wave polarization, to improve gravitational wave detection sensitivity.

Contribution

It extends previous seismic array optimization studies to include the full nested shape of the Einstein Telescope with multiple test masses and seismic wave polarizations.

Findings

Optimal sensor placement improves noise cancellation performance.

Displacing sensors from optimal positions reduces effectiveness.

Performance varies with seismic wave polarization and frequency.

Abstract

Seismic Newtonian noise is predicted to limit the sensitivity of the Einstein Telescope. It can be reduced with coherent noise cancellation techniques using data from seismometers. To achieve the best results, it is important to place the seismic sensors in optimal positions. A preliminary study on this topic was conducted for the Einstein Telescope (ET): it focused on the optimization of the seismic array for the cancellation of Newtonian noise at an isolated test mass. In this paper, we expand the study to include the nested shape of ET, i.e., four test masses of the low-frequency interferometers at each vertex of the detector. Results are investigated in function of the polarization content of the seismic field composed of body waves. The study also examines how performance can be affected by displacing the sensor array from its optimal position or by operating at frequencies other than those used for optimization.