Thesis
Magnetic-Field Stability in Unshielded Helmholtz Coils
Washington State University
Master of Science (MS), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004541
Handle:
https://hdl.handle.net/2376/124948
Abstract
A common setup in spin-exchange optical pumping (SEOP) and other table-top experiments is some current-stabilization technique for driving a Helmholtz coil pair. The first implementation of this circuit achieved 100 ppm stability on time scales between a few seconds out to an hour by employing an external comparator driving the gate of a MOSFET in series with the coils. This design was improved by placing temperature-sensitive external circuitry (MOSFET, sensing resistors, comparator feedback resistor) onto a water-chilled aluminum block, temperature-controlled at a few degrees below room temperature to ± 0.1 ˚C. The modified circuit now achieves 2 ppm current stability over similar time scales, which allows the use of a fluxgate magnetometer (max field 1 G) outside the coils to separately correct ambient-magnetic field shifts and drifts, e.g., from the current-carrying wires powering the buildings elevator. If these additional ambient field fluctuations are measured and subtracted, the magnetic-field stability approaches 2 ppm current stability over similar time scales in an unshielded environment.
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Details
- Title
- Magnetic-Field Stability in Unshielded Helmholtz Coils
- Creators
- David Morin
- Contributors
- Brian Saam (Advisor)Mark Kuzyk (Committee Member)Brian Collins (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Physics and Astronomy, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 39
- Identifiers
- OCLC#: 1370911683; 99900898136801842
- Language
- English
- Resource Type
- Thesis