2026-09-19T13:05:32Zhttps://ecommons.cornell.edu/server/oai/requestoai:ecommons.cornell.edu:1813/1108392026-05-15T19:49:03Zcom_1813_35col_1813_47
Low, David
Fuchs, Gregory David
Selman, Bart
Nowack, Katja C.
2022-01-24T18:07:53Z
2022-01-24T18:07:53Z
2021-12
ProQuest Submission ID: 12837
ProQuest Publication ID: 28777139
https://hdl.handle.net/1813/110839
https://doi.org/10.7298/xxa1-4w48
15312699
122 pages
Superconducting quantum interference devices, or SQUIDs, are highly sensitiveto magnetic flux and can be used to perform magnetic imaging at cryogenic tem- peratures. In this dissertation, I describe the first scanning SQUID microscope in a cryogen-free dilution refrigerator. First, I briefly describe basic SQUID theory, how to perform scanning SQUID microscopy, and how to design SQUIDs suited for microscopy. Next, I discuss both the apparatus and method to systematically characterize SQUIDs. I demonstrate that while heuristics provide guidance for finding low noise operating points, one often misses the best noise performance of the SQUID found by a systematic search. I also briefly discuss how to use ma- chine learning to predict SQUID noise. I then describe in depth the design of the SQUID microscope, focusing on explaining the reasons behind various features of the coldfinger and microscope. Finally, I describe how to characterize vibrations in our microscope using images of a vortex in a superconductor.
en
Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/
Constructing and Characterizing a Scanning SQUID Microscope for a Cryogen Free Dilution Refrigerator
dissertation or thesis
https://newcatalog.library.cornell.edu/catalog/15312699
application/pdf
Applied Physics
Cornell University
Doctor of Philosophy
Ph. D., Applied Physics
https://hdl.handle.net/1813/59810.2
Publication
Cornell Theses and Dissertations
Low, David
5893a6ea-7af3-41d7-abc6-04bcd26ab5df
open.access
open.access
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<Abstract>Superconducting quantum interference devices, or SQUIDs, are highly sensitiveto magnetic flux and can be used to perform magnetic imaging at cryogenic tem- peratures. In this dissertation, I describe the first scanning SQUID microscope in a cryogen-free dilution refrigerator. First, I briefly describe basic SQUID theory, how to perform scanning SQUID microscopy, and how to design SQUIDs suited for microscopy. Next, I discuss both the apparatus and method to systematically characterize SQUIDs. I demonstrate that while heuristics provide guidance for finding low noise operating points, one often misses the best noise performance of the SQUID found by a systematic search. I also briefly discuss how to use ma- chine learning to predict SQUID noise. I then describe in depth the design of the SQUID microscope, focusing on explaining the reasons behind various features of the coldfinger and microscope. Finally, I describe how to characterize vibrations in our microscope using images of a vortex in a superconductor.</Abstract>
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