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Title: A novel measurement device for use in multiphase helium-3 and 4 at ultra-low temperatures
Author: Lawson, Christopher Robert
Awarding Body: Lancaster University
Current Institution: Lancaster University
Date of Award: 2013
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This thesis details the design, construction and operation of a novel measurement device in multiphase 3He and 4He. The experiments detailed herein have lead to measurements of the 3He normal fluid viscosity and the discovery of an anomalous damping effect in superfluid 3He-B at ultra-low temperatures. The development of this device arose from the desire for a low . temperature tool which could be moved in an arbitrary fashion whilst in an ultra-low temperature environment. The device itself is a large NbTi wire goalpost-shaped oscillator with dimensions of order 10 x 20 mm. This gives the oscillator a low natural resonant frequency of around 60 Hz and a low Q-value, leading to it being termed the "Floppy Wire". When placed in a vertical magnetic field the Floppy Wire can be driven at its resonant frequency by an alternating current, the velocity of the movement being inferred from the induced Faraday voltage. Uniquely, the Floppy Wire may also be moved to any desired position when driven by an arbitrary force; for example a step or linear ramp. In order to infer the position of the Floppy Wire when operated in this manner one or more pick-up coils are used to measure the induced voltage from a high-frequency probe current that is simultaneously passed through the wire.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available