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Title: Progress towards a new experiment to search for the electric dipole moment of the neutron using ultra-cold neutrons.
Author: Sumner, T. J.
ISNI:       0000 0001 3489 9294
Awarding Body: University of Sussex
Current Institution: University of Sussex
Date of Award: 1979
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A proposed exper.1ment to search for the electric dipole moment .'/- ) (EDM) of the neutron requires a static magnetic field of 10-6 Tesla with a time stability of 10-12 T over 30 s periods (in a laboratory environment with 10-7 T fluctuations) and a spatial homcqene i.t y better than 3.10-8 Tim. Due to the size of the apparatus conventional magnetic shields seemed to be the obvious way of achieving this. However, at the time, this level of stability, and indeed measurement of a total magnetic field of this magnitude, were not obtainable without further research into both magnetic shields and total field measuring magnetometers. A prototype four-layer magnetic shield was designed and built, and results from this prototype, together with some progress in shielding theory, enabled a final shielding assembly to be designed. Preliminary measurements on this final assembly indicate shielding factors in good agreement with theory. At the same time a rubidium vapour optically pumped magnetometer, using paraffin coated absorption cells, was designed and built. Operation with a sensitivity of 1·6.10 -12 T (10 s time constant) was obtained. Finally, as a prelude to the EDM experiment, e Simple twoflow time-dependent model is proposed for ultra-cold neutron (UCN) propagation along guide tubes as an attempt to explain some unexpectedly long time constants seen in emptying UCN from a storage vessel.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available