arXiv subjects

Thomas P. Satterthwaite

Publications and source records attributed to Thomas P. Satterthwaite.

8 recordsLinked to original sources

arXiv2026

The Simons Observatory: Design and Initial Performance of the Detector Readout System for the Large-Aperture Telescope

We present the design, implementation, and initial performance of a highly multiplexed cryogenic superconducting detector readout system in the context of its deployment to the Simons Observatory large-aperture telescope (LAT). The Simons Observatory is a cosmic microwave background experiment located at 5,200 m in Chile's Atacama Desert. In addition to its 6 m LAT, whose broad range of science goals spans probing large-scale structure to searching for new Solar System objects, the observatory also currently includes three 0.42 m small-aperture telescopes, which search for signatures of primordial gravitational waves. Nearly 100,000 optically-coupled transition-edge sensor bolometers have been deployed across the observatory's four telescopes to enable these science goals. The readout systems for these telescopes use microwave frequency multiplexing to simultaneously read out 860 optically-coupled bolometers per transmission line. This is enabled by the large-scale fabrication of multiplexing chips which house radio-frequency superconducting quantum interference devices for each detector, and the development of room-temperature electronics to read out these bolometers. This has enabled the largest deployment of superconducting sensors for astronomical observations to date. This paper focuses on the design and implementation of the readout system for the 63,000 detectors in the LAT's cryogenic receiver. We present performance results from an early phase in the telescope's operation. We show that the readout system's performance enables the instrument to meet key benchmarks, including successful readout of 81.4% of its optically-coupled bolometers, which exceeds projections, and readout noise-equivalent current consistent with pre-deployment specifications.

astro-ph.IM↗

arXiv2026

The Simons Observatory: Commissioning of the Mid-Frequency Small Aperture Telescopes

The Simons Observatory (SO) is a cosmic microwave background (CMB) survey experiment observing from an altitude of 5,200 m in the Atacama Desert in Chile. The SO Small Aperture Telescopes (SATs) will cover six spectral bands between 30 and 280 GHz primarily to search for evidence of primordial gravitational waves in the large angular scale $B$-modes of the CMB polarization. The first two Mid-Frequency (MF) SATs, operating in the 90 and 150 GHz frequency bands, began commissioning observations in late 2023, and we present the results of those observations here. Each MF SAT operates with approximately 9,400 biased transition-edge sensors (TES) at 1 mm of precipitable water vapor (PWV), representing a typical 80% yield. Planet observations confirm the telescope optics performance, calibrate the instrument response, and measure the end-to-end optical efficiency of the SATs. The realized instrument efficiencies are within the range expected based on instrument model predictions. In nominal observing conditions, the noise equivalent temperatures from both telescopes combined are $2.4~\mathrm{μK_{CMB}\sqrt{s}}$ at 90 GHz and $3.2~\mathrm{μK_{CMB}\sqrt{s}}$ at 150 GHz, substantially outperforming the baseline instantaneous sensitivity targets for the observatory.

astro-ph.IM↗

arXiv2025

Construction of proANUBIS: A proof-of-concept detector for the ANUBIS experiment

The ANUBIS experiment aims to search for long-lived particles at the Large Hadron Collider (LHC) at CERN. To assess the feasibility of the project, a prototype detector, proANUBIS, was designed, constructed, and prepared for installation in the UX1 ATLAS experimental cavern at the LHC. The primary physics goals of proANUBIS are to determine the technical limitations of the detector technology and to explore the ANUBIS detector concept through in-situ measurements of muon and hadron fluxes inside the ATLAS cavern, which can be used to refine Monte Carlo simulations of such fluxes further. This report describes the design and construction of the proANUBIS experimental setup using Resistive Plate Chambers (RPCs), highlighting the possible future use case of the technology for ANUBIS. Details on the RPC technology, construction processes, quality control measures, and performance studies are discussed. Furthermore, the RPC front-end on-detector electronics and data acquisition components of proANUBIS are presented.

hep-ex↗

arXiv2025

The Simons Observatory: Studies of Phase Drift in RF Transmission Lines from the First Large-Scale Deployment of Microwave Frequency Multiplexing for Cosmology

Fulfilling the science goals of the Simons Observatory, a state-of-the-art cosmic microwave background (CMB) experiment, has required deploying tens of thousands of superconducting bolometers. Reading out data from the observatory's more than 67,000 transition-edge sensor (TES) detectors while maintaining cryogenic conditions requires an effective multiplexing scheme. The SLAC microresonator radio frequency (SMuRF) electronics have been developed to provide the warm electronics for a high-density microwave frequency multiplexing readout system, and this system has been shown to achieve multiplexing factors on the order of 1,000. SMuRF has recently been deployed to the Simons Observatory, which is located at 5,200 m on Cerro Toco in Chile's Atacama Desert. As the SMuRF system is exposed to the desert's diurnal temperature swings, resulting phase drift in RF transmission lines may introduce a systematic signal contamination. We present studies of phase drift in the room-temperature RF lines of the Simons Observatory's 6 m large-aperture telescope, which hosts the largest deployment to date of TES microwave frequency multiplexing to a single telescope. We show that these phase drifts occur on time scales which are significantly longer than sky scanning, and that their contribution to on-sky in-transition detector noise is within the readout noise budget.

astro-ph.IM↗

arXiv2025

Simons Observatory: Characterization of the Large Aperture Telescope Receiver

The Simons Observatory (SO) is a ground-based cosmic microwave background (CMB) survey experiment that currently consists of three 0.42m small-aperture telescopes (SATs) and one 6m large-aperture telescope (LAT), located at an elevation of 5200m in the Atacama Desert in Chile. At the LAT's focal plane, SO will install >62,000 transition-edge sensor detectors across 13 optics tubes (OTs) within the Large Aperture Telescope Receiver (LATR), the largest cryogenic camera ever built to observe the CMB. Here we report on the validation of the LATR in the laboratory and the subsequent dark testing and validation within the LAT. We show that the LATR meets cryogenic, optical, and detector specifications required for high-sensitivity measurements of the CMB. At the time of writing, the LATR is installed in the LAT with six OTs (corresponding to >31,000 detectors), and the LAT mirrors and remaining seven OTs are undergoing development.

astro-ph.IM↗

arXiv2024

The Simons Observatory: Dark Characterization of the Large Aperture Telescope

The Simons Observatory (SO) is a cosmic microwave background experiment composed of three 0.42 m Small Aperture Telescopes (SATs) and one 6 m Large Aperture Telescope (LAT) in the Atacama Desert of Chile. The Large Aperture Telescope Receiver (LATR) was integrated into the LAT in August 2023; however, because mirrors were not yet installed, the LATR optical chain was capped at the 4K stage. In this dark configuration we are able to characterize many elements of the instrument without contributions from atmospheric noise. Here we show this noise is below the required upper limit and its features are well described with a simple noise model. Maps produced using this noise model have properties that are in good agreement with the white noise levels of our dark data. Additionally, we show that our nominal scan strategy has a minimal effect on the noise when compared to the noise when the telescope is stationary

astro-ph.IM↗

arXiv2024

The Simons Observatory: Studies of Detector Yield and Readout Noise From the First Large-Scale Deployment of Microwave Multiplexing at the Large Aperture Telescope

The Simons Observatory is a new ground-based cosmic microwave background experiment, which is currently being commissioned in Chile's Atacama Desert. During its survey, the observatory's small aperture telescopes will map 10% of the sky in bands centered at frequencies ranging from 27 to 280 GHz to constrain cosmic inflation models, and its large aperture telescope will map 40% of the sky in the same bands to constrain cosmological parameters and use weak lensing to study large-scale structure. To achieve these science goals, the Simons Observatory is deploying these telescopes' receivers with 60,000 state-of-the-art superconducting transition-edge sensor bolometers for its first five year survey. Reading out this unprecedented number of cryogenic sensors, however, required the development of a novel readout system. The SMuRF electronics were developed to enable high-density readout of superconducting sensors using cryogenic microwave SQUID multiplexing technology. The commissioning of the SMuRF systems at the Simons Observatory is the largest deployment to date of microwave multiplexing technology for transition-edge sensors. In this paper, we show that a significant fraction of the systems deployed so far to the Simons Observatory's large aperture telescope meet baseline specifications for detector yield and readout noise in this early phase of commissioning.

astro-ph.IM↗

arXiv2021

AbacusSummit: A Massive Set of High-Accuracy, High-Resolution $N$-Body Simulations

We present the public data release of the AbacusSummit cosmological $N$-body simulation suite, produced with the $\texttt{Abacus}$ $N$-body code on the Summit supercomputer of the Oak Ridge Leadership Computing Facility. $\texttt{Abacus}$ achieves $\mathcal{O}\left(10^{-5}\right)$ median fractional force error at superlative speeds, calculating 70M particle updates per second per node at early times, and 45M particle updates per second per node at late times. The simulation suite totals roughly 60 trillion particles, the core of which is a set of 139 simulations with particle mass $2\times10^{9}\,h^{-1}\mathrm{M}_\odot$ in box size $2\,h^{-1}\mathrm{Gpc}$. The suite spans 97 cosmological models, including Planck 2018, previous flagship simulation cosmologies, and a linear derivative and cosmic emulator grid. A sub-suite of 1883 boxes of size $500\,h^{-1}\mathrm{Mpc}$ is available for covariance estimation. AbacusSummit data products span 33 epochs from $z=8$ to $0.1$ and include lightcones, full particle snapshots, halo catalogs, and particle subsets sampled consistently across redshift. AbacusSummit is the largest high-accuracy cosmological $N$-body data set produced to date.

astro-ph.CO↗