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Title: Accumulation and manipulation of positron plasmas for antihydrogen production
Author: Watson, T. L.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2004
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This thesis describes a buffer gas positron accumulator which has been used by the ATHENA collaboration to produce and detect the first cold antihydrogen atoms. In particular, the work presented is centred on the implementation of a so-called rotating wall electric field to compress a positron plasma in preparation for recombination with antiprotons, in addition to maximising the accumulation efficiency by the automatic optimisation of the trap applied potentials. Central results include successful compression of the positron plasma with an increase in central density by a factor of six. The use of a rotating wall during accumulation of a positron plasma has been investigated for the first time with interesting distinctions observed when compared to a typical accumulation without the use of a rotating wall. Results show that its application results in a greater number of positrons being accumulated at a given time, and that there appears to be an optimum, pressure dependent, time at which to apply the rotating wall. Results also indicate that the accumulation time at which the plasma is maximally compressed is also pressure dependent. A useful program has also been written, and successfully implemented that automatically optimises the electrode array applied potentials to maximise the trapping efficiency after the growth of new solid neon moderators.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available