Magnetic aspects of the Cryo-nEDM experiment

Katsika, Aikaterini G (2013) Magnetic aspects of the Cryo-nEDM experiment. Doctoral thesis (PhD), University of Sussex.

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The provision of a temporally stable and spatially uniform magnetic field is a precondition for the Cryo-nEDM experiment to conduct a successful measurement. These two aspects and some further data analysis are largely the subjects of my thesis.

I propose a technique to improve the current dynamic magnetic shielding of the existing apparatus by more than 2 orders of magnitude without distorting the homogeneity of the magnetic field more than the limitations set on the proposal. By testing a 12.5 th scale model of the apparatus I have shown that the placement of a 1m long superconducting
shield inside the solenoid can improve the magnetic shielding by at least a factor of 500.

Magnetostatic simulations have been carried out for the full model of the experimental apparatus to investigate the effect of various parts to the magnetic field configuration over the neutron guides and the storage bottles. This model can be considered as a basis on which further additions can be made if needed.

The actual response of the 21 compensation coils has been measured experimentally. This information was used to develop a systematic method to calculate the optimum
currents for these coils to smooth the magnetic field inhomogeneities in the area of the storage cells of neutrons. Applying this method to the existing apparatus, it has been estimated that we can increase the T2 relaxation time from 2 seconds to more than 20 seconds.

Finally, I have analysed the data taken over winter 2010 run in terms of neutrons polarisation. As a result, very useful information was extracted for the issues that have to be resolved and taken into account in future runs to improve the polarisation of neutrons and therefore the sensitivity of the experiment.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics > QC0770 Nuclear and particle physics. Atomic energy. Radioactivity > QC0793 Elementary particle physics
Depositing User: Library Cataloguing
Date Deposited: 28 Jun 2013 10:46
Last Modified: 08 Sep 2015 15:08

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