Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver

Caleb H. Wheeler, Marko Neric, Christopher Groppi, Matthew Underhill, Hamdi Mani, Sander Weinreb, Damon S. Russell, Jacob W. Kooi, Arthur W. Lichtenberger, Christopher K. Walker, Craig Kulesa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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.

Original languageEnglish (US)
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII
PublisherSPIE
Volume9914
ISBN (Electronic)9781510602076
DOIs
Publication statusPublished - 2016
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII - Edinburgh, United Kingdom
Duration: Jun 28 2016Jul 1 2016

Other

OtherMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII
CountryUnited Kingdom
CityEdinburgh
Period6/28/167/1/16

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Keywords

  • Array Receivers
  • Heterodyne
  • KAPPa
  • SIS junction
  • THz

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Wheeler, C. H., Neric, M., Groppi, C., Underhill, M., Mani, H., Weinreb, S., ... Kulesa, C. (2016). Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver. In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII (Vol. 9914). [99141W] SPIE. https://doi.org/10.1117/12.2231358