arXiv subjects

Fabián Erasmo Peña Arellano

Publications and source records attributed to Fabián Erasmo Peña Arellano.

4 recordsLinked to original sources

arXiv2026

A dual tunnel structure for the Einstein Telescope

We present a novel tunnel architecture for the Einstein Telescope that departs from the traditional large-cavern approach and reduces the excavated volume by an order of magnitude. In the proposed design, seismic isolation systems are housed in raise-bore wells extending upward from the main tunnel toward an upper service tunnel. The preisolators for the most sensitive optics are located in the service tunnel, supported directly on strong rock, whereas the other filters are distributed along the wells within compact, side-access vacuum chambers. Shorter, separate wells accommodate the seismic isolation systems for less demanding optics. This configuration provides substantial advantages: easier lock acquisition and improved robustness of the interferometers, lower-frequency pendulum stages, reduced congestion around the test masses, simplified installation and maintenance, improved vacuum partitioning, strong physical decoupling between the high- and low-frequency interferometers, and compatibility with advanced sensors for Newtonian-noise cancellation.

astro-ph.IM↗

arXiv2025

Optimizing Active Seismic Isolation Systems in Gravitational-Wave Detectors

Gravitational wave detectors such as KAGRA, a 3-km long underground laser interferometer in Japan, require elaborate passive and active seismic isolation of their mirrors. With the aim of detecting passing gravitational waves that create a relative mirror displacement of less than $10^{-22}\ \mathrm{m}$ at frequencies of tens to hundreds of Hz, all environmental couplings must be stringently suppressed. This paper presents the result of applying the H-infinity optimization method to the active seismic isolation of a gravitational-wave detector for the first time. The so-called \textit{sensor correction} and \textit{sensor fusion} schemes of the seismic attenuation system of KAGRA's signal recycling mirror are used as a test bed. We designed and implemented optimal sensor correction and sensor fusion filters, resulting in a sevenfold attenuation of seismic noise coupling to the signal recycling mirror in the 0.1-0.5 Hz band, with the downstream effect of an 88.2% noise performance improvement in the same frequency band. When combined with other hardware upgrades, the implementation of sensor correction and sensor fusion contributed to an increase in KAGRA's duty cycle from 53% in the O3GK observation run to 80% in O4a, demonstrating the effectiveness of the H-infinity optimization approach.

physics.ins-det↗

arXiv2020

Compact integrated optical sensors and electromagnetic actuators for vibration isolation systems in the gravitational-wave detector KAGRA

This paper reports on the design and characteristics of a compact module integrating an optical displacement sensor and an electromagnetic actuator for use with vibration-isolation systems installed in KAGRA, the 3-km baseline gravitational-wave detector in Japan. In technical concept, the module belongs to a family tree of similar modules called OSEMs, used in other interferometric gravitational-wave detector projects. After the initial test run of KAGRA in 2016, the sensor part, which is a type of slot sensor, was modified by increasing the spacing of the slot from 5 mm to 15 mm to avoid the risk of mechanical interference with the sensor flag. We confirm the sensor performance is comparable to that of the previous design despite the modification. We also confirm the sensor noise is consistent with the theoretical noise budget. The noise level is 0.5 nm/rtHz at 1 Hz and 0.1 nm/rtHz at 10 Hz, and the linear range of the sensor is 0.7 mm or more. We measured the response of the actuator to be 1 N/A, and also measured the resistances and inductances of coils of the actuators to confirm consistency with theory. Coupling coefficients among the different degrees of freedom were also measured and shown to be negligible, varying little between designs. A potential concern about thermal noise contribution due to eddy current loss is discussed. As of 2020, 42 of the modules are in operation at the site.

astro-ph.IM↗

arXiv2019

Mirror actuation design for the interferometer control of the KAGRA gravitational wave telescope

KAGRA is a 3-km cryogenic interferometric gravitational wave telescope located at an underground site in Japan. In order to achieve its target sensitivity, the relative positions of the mirrors of the interferometer must be finely adjusted with attached actuators. We have developed a model to simulate the length control loops of the KAGRA interferometer with realistic suspension responses and various noises for mirror actuation. Using our model, we have designed the actuation parameters to have sufficient force range to acquire lock as well as to control all the length degrees of freedom without introducing excess noise.

physics.ins-det↗