Emerging Researchers National (ERN) Conference

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Circuit Board Design and Impedance Testing for the Atacama Cosmology

Undergraduate #353
Discipline: Technology and Engineering
Subcategory: Electrical Engineering

Lenoi K. Carter - Onondaga Community College

The Atacama Cosmology Telescope (ACT) is an instrument that measures the Cosmic Microwave Background (CMB) temperature and polarization in unprecedented detail enabling a wide range of science objectives. In order to accurately measure the tiny variations in temperature of the CMB, detectors inside ACT are cooled to 100 mK. Many of the components inside ACT, including the wires used to transmit signals to and from the detectors, are superconducting at these low temperatures. This causes the electrical properties of the materials to change drastically, affecting the quality of the signals that are transmitted to the detectors. The number of detectors inside ACT is directly proportional to the mapping speed of the instrument to the CMB which drives the need to observe with as many detectors as possible. To increase the number of detectors, the settling times of manganin twisted pair wires used to communicate with the detectors in the telescope were analyzed to determine if the properties of the wire would affect the quality of the transmitted signals. We find that the manganin wires in ACT are unlikely to limit ACT’s readout performance; however, further investigations are underway to conduct similar tests on the wire at cryogenic temperatures. In moving towards increasing the number of detectors, a circuit board was also designed to interface with the new Superconducting Quantum Interference Device (SQUID) chips that are needed to readout the increased number of detectors that will be deployed on ACT. Tests are being carried out on this board before it can be deployed on the telescope. Finally, it is important to accurately characterize the resistance and superconducting transition temperature of a variety of components used in the detector arrays; thus, circuit boards used for four-lead resistance measurements of circuit components were modified to enable new and more efficient tests to be done.

Funder Acknowledgement(s): Funding was provided by the NSF/LSAMP grant to Upstate LSAMP.

Faculty Advisor: Michael D. Niemack, niemack@cornell.edu

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This material is based upon work supported by the National Science Foundation (NSF) under Grant No. DUE-1930047. Any opinions, findings, interpretations, conclusions or recommendations expressed in this material are those of its authors and do not represent the views of the AAAS Board of Directors, the Council of AAAS, AAAS’ membership or the National Science Foundation.