Yao, Han;
(2024)
High-sensitivity unshielded radio-frequency atomic magnetometers.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis presents an experimental approach to improve the performances of an unshielded single-cell radio-frequency atomic magnetometer (RF-AM) operating in a magnetically noisy environment. Starting with the background and basic principles, the thesis then demonstrates and quantifies improvement in the sensitivity of the magnetometer by sequentially introducing the following modifications in the set-up: in-situ active cancellation of low-frequency magnetic noise, counter-propagating pumping and multi-pass probing. For this configuration, a detailed optimisation of the experimental parameters was performed, which led to an improvement in sensitivity of over a factor of three with respect to our previous single-cell single-pump magnetometer. In addition to the upgrades of the hardware setup, optimisation algorithms were introduced. Specifically, this thesis describes the optimisation of the collection of data of the unshielded RF-AM based on the uniform design of the experimental parameters space. The proposed procedure is shown to lead to the efficient optimisation of the atomic magnetometer at different frequencies, and it is applicable to both AC and DC sensitivity optimisation. The procedure does not require any detailed prior knowledge of the model underlying the operation of the RF-AM and is effective in reducing the number of experimental runs required for the optimisation. It is ideally suited to the self-calibration of devices without human supervision. For the selection of the optimal operating conditions, general regression neural networks were demonstrated as an effective tool to operate on a small sample of data as input.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | High-sensitivity unshielded radio-frequency atomic magnetometers |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10186122 |
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