Advanced ACTPol is an instrument upgrade for the six-meter Atacama Cosmology Telescope (ACT) designed to measure the cosmic microwave background (CMB) temperature and polarization with arcminute-scale angular resolution. To achieve its science goals, Advanced ACTPol utilizes a larger readout multiplexing factor than any previous CMB experiment to measure detector arrays with approximately two thousand transition-edge sensor (TES) bolometers in each 150 mm detector wafer. We present the implementation and testing of the Advanced ACTPol time-division multiplexing readout architecture with a 64-row multiplexing factor. This includes testing of individual multichroic detector pixels and superconducting quantum interference device (SQUID) multiplexing chips as well as testing and optimizing of the integrated readout electronics. In particular, we describe the new automated multiplexing SQUID tuning procedure developed to select and optimize the thousands of SQUID parameters required to readout each Advanced ACTPol array. The multichroic detector pixels in each array use separate channels for each polarization and each of the two frequencies, such that four TESes must be read out per pixel. Challenges addressed include doubling the number of detectors per multiplexed readout channel compared to ACTPol and optimizing the Nyquist inductance to minimize detector and SQUID noise aliasing.
@article{arxiv.1607.06064,
title = {Readout of two-kilopixel transition-edge sensor arrays for Advanced ACTPol},
author = {Shawn W. Henderson and Jason R. Stevens and Mandana Amiri and Jason Austermann and James A. Beall and Saptarshi Chaudhuri and Hsiao-Mei Cho and Steve K. Choi and Nicholas F. Cothard and Kevin T. Crowley and Shannon M. Duff and Colin P. Fitzgerald and Patricio A. Gallardo and Mark Halpern and Matthew Hasselfield and Gene Hilton and Shuay-Pwu Patty Ho and Johannes Hubmayr and Kent D. Irwin and Brian J. Koopman and Dale Li and Yaqiong Li and Jeff McMahon and Federico Nati and Michael D. Niemack and Carl D. Reintsema and Maria Salatino and Alessandro Schillaci and Benjamin L. Schmitt and Sara M. Simon and Suzanne T. Staggs and Eve M. Vavagiakis and Jonathan T. Ward},
journal= {arXiv preprint arXiv:1607.06064},
year = {2017}
}
Comments
17 pages, 6 figures. To be published in Proc. SPIE. Presented at SPIE Astronomical Telescopes + Instrumentation Conference 9914: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, July 2016