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New Source of Dense, Cryogenic Positron Plasmas / L Jørgensen; M Amoretti; G Bonomi; P Bowe; C Canali; C Carraro; C Cesar; M Charlton; M Doser; A Fontana; M Fujiwara; R Funakoshi; P Genova; J Hangst; R Hayano; A Kellerbauer; V Lagomarsino; R Landua; E. Lodi Rizzini; M Macrì; N Madsen; D Mitchard; P Montagna; A Rotondi; G Testera; A Variola; L Venturelli; D. van der Werf; Y Yamazaki; Dirk van der Werf

Physical Review Letters, Volume: 95, Issue: 2

Swansea University Author:

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DOI (Published version): 10.1103/PhysRevLett.95.025002

Abstract

We have developed a new method, based on the ballistic transfer of preaccumulated plasmas, to obtain large and dense positron plasmas in a cryogenic environment. The method involves transferring plasmas emanating from a region with a low magnetic field (0.14 T) and relatively high pressure (10^{-9}...

Full description

Published in: Physical Review Letters 0031-9007 1079-7114 2005 https://cronfa.swan.ac.uk/Record/cronfa1555 No Tags, Be the first to tag this record!
Abstract: We have developed a new method, based on the ballistic transfer of preaccumulated plasmas, to obtain large and dense positron plasmas in a cryogenic environment. The method involves transferring plasmas emanating from a region with a low magnetic field (0.14 T) and relatively high pressure (10^{-9} mbar) into a 15 K Penning-Malmberg trap immersed in a 3 T magnetic field with a base pressure better than 10^{-13} mbar. The achieved positron accumulation rate in the high field cryogenic trap is more than one and a half orders of magnitude higher than the previous most efficient UHV compatible scheme. Subsequent stacking resulted in a plasma containing more than 1.2 \times 10^9 positrons, which is a factor 4 higher than previously reported. Using a rotating wall electric field, plasmas containing about 2 \times 10^6 positrons were compressed to a density of 2.6 \times 10^{10} cm^3. This is a factor of 6 improvement over earlier measurements. This paper describes the development of a new method to obtain large, dense positron plasmas in a cryogenic environment. Van der Werf was the project leader for the positron accumulator and implemented the positron transfer from the low field, room temperature, region to the high field, cryogenic temperature area. College of Science 2