arXiv subjects

K. Toland

Publications and source records attributed to K. Toland.

2 recordsLinked to original sources

arXiv2026

LIGO A$^\sharp$: Detector Design and Science Prospects Beyond A+

We present the LIGO A$^\sharp$ detector concept, an upgrade for the LIGO observatories based on room-temperature interferometers beyond the fifth observing run (O5). Building on the A+ sensitivity, A$^\sharp$ targets broadband sensitivity improvements through heavier test masses, improved suspensions and seismic isolation, increased arm-cavity power, enhanced frequency-dependent squeezing, reduced coating thermal noise considering two scenarios, and improved control of mechanical motion and optical modes. We describe the principal design choices, projected noise performance, and corresponding astrophysical prospects. LIGO A$^\sharp$ substantially increases compact-binary detection rates, strengthens population inference, and improves both early-warning times and localization for binary neutron star mergers. The improved sensitivity enables more detailed studies of compact-binary coalescences, including higher-order multipoles, intermediate-mass black holes, remnant black hole ringdown, and the neutron star equation of state. It also broadens the discovery potential for new gravitational-wave sources such as continuous waves and bursts, should enable detection of the stochastic background from compact binary mergers if it remains undetected after O5, and strengthens the role of gravitational-wave detectors as probes of fundamental physics. We discuss key technical challenges and the role of A$^\sharp$ as both a major scientific upgrade for the 2030s and a technology pathfinder for next-generation gravitational-wave observatories, such as Cosmic Explorer.

astro-ph.IM↗

arXiv2021

A Nineteen Day Earth Tide Measurement with a MEMS Gravimeter

The measurement of tiny variations in local gravity enables the observation of subterranean features. Gravimeters have historically been extremely expensive instruments, but usable gravity measurements have recently been conducted using MEMS (microelectromechanical systems) sensors. Such sensors are cheap to produce, since they rely on the same fabrication techniques used to produce mobile phone accelerometers. A significant challenge in the development of MEMS gravimeters is maintaining stability over long time periods, which is essential for long term monitoring applications. A standard way to demonstrate gravimeter stability and sensitivity is to measure the periodic elastic distortion of the Earth due to tidal forces - the Earth tides. Here we present a nineteen day measurement of the Earth tides, with a correlation coefficient to the theoretical signal of 0.979. The estimated bias instability of the proposed gravimeter is 8.18 microGal for an averaging time of ~400 s when considering the raw, uncompensated data. The bias instability extracted from the sensor electronic noise sits just under 2 mircoGal for an averaging time of ~200 s. After removing the long-term temperature and control electronics effects from the raw data, a linear drift of 268 microGal/day is observed in the data, which is among one of the best reported for a MEMS device. These results demonstrate that this MEMS gravimeter is capable of conducting long-therm time-lapse gravimetry, a functionality essential for applications such as volcanology.

physics.ins-det↗