Münster 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HK: Fachverband Physik der Hadronen und Kerne
HK 36: Fundamentale Symmetrien- Poster
HK 36.2: Poster
Mittwoch, 23. März 2011, 14:00–16:00, Foyer Chemie
Preparations for Photodetachment Measurements of the Negative Positronium Ion† — •Stefan Gärtner1, Hubert Ceeh2, Frank Fleischer3, Christoph Hugenschmidt2, Klaus Schreckenbach2, Dirk Schwalm4, and Peter Thirolf1 — 1LMU München, Garching — 2TU München and FRM II, Garching — 3University of Washington, Seattle — 4MPI f. Kernphysik, Heidelberg
After the recent successful high-precision measurement of the Ps− ion (e+e−e−) decay rate by our group (Γ = 2.087(7) ns−1 [1]), preparations of a photodetachment experiment of this fundamental three-body system are on their way 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). A photodetachment rate of the order of at least 40 s−1 is expected, which might be increased significantly by operating both e+ beam and laser in pulsed mode. By using this technique, besides the first experiment targeting photoionization cross sections in Ps−, the production of an energy-variable pure ortho-positronium beam becomes viable, which then can be employed in further experiments, e. g. spectroscopy of the 13S1 → 23S1 transition in positronium. Currently, the positron source is upgraded to yield an intensity significantly higher than the current ≈ 9 · 108 moderated positrons per second. [1] H. Ceeh et al., to be published. [2] A. Igarashi et al., New J. Phys. 2, 17 (2000). †Supported by DFG under contract HA1101/13-1.