Berlin 2005 – scientific programme
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TT: Tiefe Temperaturen
TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique
TT 16.34: Poster
Saturday, March 5, 2005, 11:00–16:30, Poster TU C
Charge Transport Through Quench-Condensed Hydrogen Films — •Jörg Angrik, Patrick Schwinzer, Jürgen Klier, and Paul Leiderer — Fachbereich Physik, Universität Konstanz, Postfach M676, D-78457 Konstanz
The self-charging of quench-condensed tritium films prevents their use as a source in the next generation direct neutrino mass experiments. The KATRIN experiment, which is set up at the Forschungszentrum Karlsruhe, is the successor of the Mainz neutrino mass experiment, where such films were used. As the resolution of the KATRIN experiment will be in the sub-eV range, the self-charging effect cannot be tolerated. While the mobility of positive charges (3He+, originating from the β-decay) is well understood in terms of a thermal hopping model in a critical electric field (Ec ≈ 62 MV/cm at 1.9 K), little is known about the transport of negative charges. Hence we place electrons on top of hydrogen films, which then form surface states, and investigate their transport through the films. Hereby hydrogen, and also deuterium, are used to model the tritium films. As the transport is supposed to be strongly dependent on the structure of the, e.g., quench-condensed, films, we focus on preparation procedures and treatments in order to increase the conductivity of the electrons or discharge of the films.