Paper
20 July 2016 Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver
Caleb H. Wheeler, Marko Neric, Christopher E. Groppi, Matthew Underhill, Hamdi Mani, Sander Weinreb, Damon S. Russell, Jacob W. Kooi, Arthur W. Lichtenberger, Christopher K. Walker, Craig Kulesa
Author Affiliations +
Abstract
We present the results from the magnetic field generation within the Kilopixel Array Pathfinder Project (KAPPa) instrument. The KAPPa instrument is a terahertz heterodyne receiver using a Superconducting-Insulating- Superconducting (SIS) mixers. To improve performance, SIS mixers require a magnetic field to suppress Josephson noise. The KAPPa test receiver can house a tunable electromagnet used to optimize the applied magnetic field. The receiver is also capable of accommodating a permanent magnet that applies a fixed field. Our permanent magnet design uses off-the-shelf neodymium permanent magnets and then reshapes the magnetic field using machined steel concentrators. These concentrators allow the use of an unmachined permanent magnet in the back of the detector block while two small posts provide the required magnetic field across the SIS junction in the detector cavity. The KAPPa test receiver is uniquely suited to compare the permanent magnet and electromagnet receiver performance. The current work includes our design of a ‘U’ shaped permanent magnet, the testing and calibration procedure for the permanent magnet, and the overall results of the performance comparison between the electromagnet and the permanent magnet counterpart.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Caleb H. Wheeler, Marko Neric, Christopher E. Groppi, Matthew Underhill, Hamdi Mani, Sander Weinreb, Damon S. Russell, Jacob W. Kooi, Arthur W. Lichtenberger, Christopher K. Walker, and Craig Kulesa "Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver", Proc. SPIE 9914, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, 99141W (20 July 2016); https://doi.org/10.1117/12.2231358
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KEYWORDS
Magnetism

Receivers

Solar concentrators

Sensors

Magnetic sensors

Heterodyning

Superconductors

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