New source of dense, cryogenic positron plasmas.
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 x 10(9) positrons, which is a factor 4 higher than previously reported. Using a rotating wall electric field, plasmas containing about 20 x 10(6) positrons were compressed to a density of 2.6 x 10(10) cm(-3). This is a factor of 6 improvement over earlier measurements.
Jørgensen
L V
LV
Department of Physics, University of Wales Swansea, Swansea SA2 8PP, United Kingdom. lars.varmingjorgensen@cern.ch
Amoretti
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Bonomi
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Bowe
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Canali
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Carraro
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Cesar
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Charlton
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Doser
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Fontana
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Fujiwara
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Funakoshi
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Genova
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Hangst
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Hayano
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Kellerbauer
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Lagomarsino
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Landua
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Lodi Rizzini
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Macrì
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Madsen
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Mitchard
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Montagna
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Rotondi
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Testera
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Variola
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Venturelli
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van der Werf
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Yamazaki
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