München 2004 – wissenschaftliches Programm
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MO: Molekülphysik
MO 17: Poster II
MO 17.21: Poster
Donnerstag, 25. März 2004, 14:00–16:00, Schellingstr. 3
Study of H3+ production and rotational de-excitation in a hollow cathode ion source — •Simon M. Altevogt1, Henrik B. Pedersen1, Vola Andrianarijaona1, Henrik Buhr1, Holger Kreckel1, Sven Krohn1, Lutz Lammich1, Daniel Strasser2, Daniel Zajfman2, Dirk Schwalm1, and Andreas Wolf1 — 1Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 2Weizman Institut of Science, 76100 Rehovot, Israel
In many plasma ion sources H3+ is produced with high rovibrational excitation (3000K). With the aim of producing rotationally cold H3+ ions a hollow cathode ion source has been built closely following a design in use in the group of Prof. H. Helm at the Universität Freiburg. The liquid nitrogen cooled source delivers a stable current of up to several µA of H3+. Detailed dependencies of the ion yield on the inside H2-gas pressure, discharge intensity and electrical extraction field strength in the ion drift region were obtained. To determine the rotational temperature of the ions, the kinetic energy release following dissociative recombination of the H3+ ions from the source with electrons at zero relative energy was measured in a merged beam setup at the heavy ion storage ring TSR. By comparing the results to Monte-Carlo simulations, it could be shown that with a suitable combination of H2-gas pressure and electrical extraction field the rotational temperature of the H3+ ions could be reduced to the level of ≈1000K.