Mainz 2012 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 50: Poster – Fundamentale Symmetrien
HK 50.1: Poster
Donnerstag, 22. März 2012, 14:00–16:00, P Foyer
Experimental setup for photodetachment studies of the negative positronium ion† — •Stefan Gärtner1, Hubert Ceeh2, Christoph Hugenschmidt2, Klaus Schreckenbach2, Dirk Schwalm3, and Peter Thirolf1 — 1LMU München, Garching — 2TU München and FRM II, Garching — 3MPI für Kernphysik, Heidelberg and Weizmann Institute, Rehovot, Israel
After the recent successful high-precision measurement of the Ps− ion (e+e−e−) decay rate by our group (Γ = 2.0875(50) ns−1 [1]), an experimental setup has been devised for photodetachment studies of this fundamental three-body system at the NEPOMUC high-flux positron source at the FRM II reactor in Garching. Theoretical calculations for the photodetachment cross section [2] will be tested in the off-resonant regime at the two wavelengths (532 nm and 1064 nm) provided by a high-power, high-repetition Nd:YAG laser (100 W average power, 10 kHz repetition rate). The principal feasibility has been shown in [3] using a reflection geometry. By employing a transmission geometry, we aim at a quantitative result and in a later stage at the production of an energy-variable pure ortho-positronium beam, which then can drive further experiments, e. g. spectroscopy of the 13S1 → 23S1 transition in positronium. First experimental results are expected mid of 2012, when the NEPOMUC upgrade to yield an intensity significantly higher than the current ≈ 9 · 108 moderated e+/s will be completed.
H. Ceeh et al., Phys. Rev. A 84, 062508 (2011).
[2] A. Igarashi et al., New J. Phys. 2, 17 (2000).
[3] K. Michishio et al., Phys. Rev. Lett. 106, 153401 (2011).
†Supported by DFG under contract HA1101/13-1.