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

Fuente: arXiv
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Main Authors: Satterthwaite, Thomas P., Ahmed, Zeeshan, Duell, Cody J., Henderson, Shawn W., Pinsonneault-Marotte, Tristan, Silva-Feaver, Max, Wang, Yuhan
Format: Preprint
Published: 2025
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_version_ 1866910018296610816
author Satterthwaite, Thomas P.
Ahmed, Zeeshan
Duell, Cody J.
Henderson, Shawn W.
Pinsonneault-Marotte, Tristan
Silva-Feaver, Max
Wang, Yuhan
author_facet Satterthwaite, Thomas P.
Ahmed, Zeeshan
Duell, Cody J.
Henderson, Shawn W.
Pinsonneault-Marotte, Tristan
Silva-Feaver, Max
Wang, Yuhan
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25726
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Simons Observatory: Studies of Phase Drift in RF Transmission Lines from the First Large-Scale Deployment of Microwave Frequency Multiplexing for Cosmology
Satterthwaite, Thomas P.
Ahmed, Zeeshan
Duell, Cody J.
Henderson, Shawn W.
Pinsonneault-Marotte, Tristan
Silva-Feaver, Max
Wang, Yuhan
Instrumentation and Methods for Astrophysics
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.
title The Simons Observatory: Studies of Phase Drift in RF Transmission Lines from the First Large-Scale Deployment of Microwave Frequency Multiplexing for Cosmology
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.25726