Recent Advances in Frequency-Multiplexed TES Readout: Vastly Reduced Parasitics and an Increase in Multiplexing Factor with sub-Kelvin SQUIDs

Abstract

Cosmic microwave background (CMB) measurements are fundamentally limited by photon statistics. Therefore, ground-based CMB observatories have been increasing the number of detectors that are simultaneously observing the sky. Thanks to the advent of monolithically fabricated transition edge sensor (TES) arrays, the number of on-sky detectors has been increasing exponentially for over a decade. The next-generation experiment CMB-S4 will increase this detector count by more than an order of magnitude from the current state-of-the-art to ~500,000. The readout of such a huge number of exquisitely precise sub-Kelvin sensors is feasible using an existing technology: frequency-domain multiplexing (fMux). To further optimize this system and reduce complexity and cost, we have recently made significant advances including the elimination of 4 K electronics, a massive decrease of parasitic in-series impedances, and a significant increase in multiplexing factor.

arXiv comment7 pages, 6 figures, Submitted to the JLTP for LTD-18

References in corpus (3)

• Frequency Multiplexed SQUID Readout of Large Bolometer Arrays for Cosmic Microwave Background Measurements
• Improved Performance of TES Bolometers using Digital Feedback
• Development of the superconducting detectors and read-out for the X-IFU instrument on board of the X-ray observatory Athena

Cited by in corpus (4)

• A Review of X-ray Microcalorimeters Based on Superconducting Transition Edge Sensors for Astrophysics and Particle Physics
• Overview of the Medium and High Frequency Telescopes of the LiteBIRD satellite mission
• Low Noise Frequency Domain Multiplexing of TES Bolometers using Sub-kelvin SQUIDs
• Monitoring TES Loop Gain in Frequency Multiplexed Readout