Test system for creation and trapping of low energy H- ions /
H+ ions as probe particles are required by a proposed antiproton gravitational acceleration experiment at Los Alamos National Laboratory. These particles are utilized to calibrate the influence of the patch effect (electric stray on a material surface) and the inhomogeneity of the magnetic field....
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743266441&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | H+ ions as probe particles are required by a proposed antiproton gravitational acceleration experiment at Los Alamos National Laboratory. These particles are utilized to calibrate the influence of the patch effect (electric stray on a material surface) and the inhomogeneity of the magnetic field. The required number of H- ions is 10,000 to 20,000 per cycle at a cycle rate of < 0.5 Hz. The use of an external H- source faces some difficulties so the in situ H-production in an ion launching trap is investigated. We have demonstrated in situ production of H-. Electron impact ionization ofH2 produces trapped H+ and H2+ and H2+,and H2 reacting with H2 produces H3+. H-is produced by surface charge exchange of the trapped positive hydrogen ions at a cesiated HAVAR(TM) trap electrode. Proper timing of switched trapping potentials projects the positive ions to the cesiated surface and subsequent further switching traps the H- ions. The overall efficiencies (conversion and trapping) were, respectively, up to 8%, 20% and 7% for (H+/H-), (H2+/H-) and H3+/H-) conversions. Their relative contributions to the H- production depend on the switching times. The absolute number of trapped H- ions from H+ is estimated to be around 56,0001︢2,000 ions for an average kinetic energy of the H- 3.30︢.5 eV. This research demonstrates the viability of this method to support an antiproton gravitational acceleration experiment. |
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| Item Description: | Vita. "Major Subject: Physics". In title, symbols are used. |
| Physical Description: | ix, 110 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |