Berlin 2005 – scientific programme
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MS: Massenspektrometrie
MS 2: Posterbeiträge
MS 2.11: Poster
Friday, March 4, 2005, 11:45–12:30, Poster HU
Spatially Resolved Uranium Trace Analysis of Grain Samples — •Ilia Strachnov1, Klaus Eberhard2, Gerhard Huber1, Sergej Karpuk1, Jochen Maul1, Gerd Passler1, Maria Carmen Roca1, Maxim Seliverstov1, Norbert Trautmann2, and Klaus Wendt1 — 1Institut für Physik, Staudingerweg 7, 55099 Mainz — 2Institut für Kernchemie, Fritz-Strassmann-Weg 2, 55099 Mainz
A method for spatially resolved isotope-selective determination of actinides in dust grains is presented. In a first step metal samples and salt grains have been investigated. A BRUKER MALDI-TOF mass spectrometer has been equipped with additional pulsed laser beams for postionization. The built-in nitrogen laser is focused with moderate pulse energy on the target surface. Neutral atoms and ions are desorbed. The ions can be completely suppressed by an additional electric field pulse repelling them back to the target. With a delay of 600 ns the atoms are selectively ionized with the additional laser beams by multi-step resonant excitation. Resonant two step excitation with dye lasers has been combined with an IR ionization step for high atom selectivity. The detection of molecular compounds could be enhanced using non-resonant UV light at λ= 355 nm. The photo-ions are extracted after 1µs and analyzed by the TOF spectrometer in the linear or reflectron modes.