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Title: Permanent magnet based magnetic resonance sensors
Author: Parslow, Steven Thomas
ISNI:       0000 0004 9355 6461
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2019
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In 2006 patent EP2069769A2 described using magnetic resonance (MR), instead of fluorescence, as the detection method for microarrays. This covered the concept of binding magnetic particles, such as Superparamagnetic Iron Oxide (SPIO), to a surface in order to change the MR signal that would normally be expected from the fluid covering the surface to which the particles were bound. In this thesis, measurement techniques are presented, utilising both pulsed and continuous wave nuclear magnetic resonance (CWNMR), where surface bound magnetic nanoparticles disrupt the MR signal that would normally be detected in the fluid covering the surface, using low magnetic field sensors constructed from permanent magnets. A pulsed technique is presented with a sensor constructed using permanent magnets in a Halbach arrangement. Using a technique called Magnetic Resonance Disruption (MaRDi), it is shown that the T2eff relaxation time of a test liquid, polydimethylsiloxane (PDMS), reduces as the proportion of the surface area covered with SPIO increases. In addition, a linear decrease in the signal amplitude from the PDMS as a function of SPIO coverage, which is observed both for an integral over 4096 NMR echoes and even just in the first echo. The latter result suggests the potential for a technique to be developed with simplified and low cost electronics. A CWNMR technique is also presented by revisiting the Look and Locker’s tone-burst experiments but modified to use a commercial marginal oscillator. Though observing the transient effect when a sweep coil is switched on, a parameter Tx can be determined that is related to relaxation time T1 that can subsequently be calculated with the aid of calibration samples. This Transient Effect Determination of Spin Lattice relaxation time (TEDSpiL) was automated using low cost microcontrollers. A potential industrial application of detecting moisture uptake through improperly stored dehydrated milk powder is also presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available