Hannover 2010 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 9: Ionenfallen und FT-IZR-MS, Moleküle, Cluster und Reaktionen

MS 9.4: Talk

Friday, March 12, 2010, 11:30–11:45, F 428

Ion bunching properties at extremely high vacuum in the Cryogenic Trap for Fast ion beams (CTF) — •Michael Froese¹, Klaus Blaum¹, Florian Fellenberger¹, Manfred Grieser¹, Oded Heber², Michael Lange¹, Felix Laux¹, Sebastian Menk¹, Dmitry A. Orlov¹, Roland Repnow¹, Thomas Sieber¹, Yoni Toker², Robert von Hahn¹, and Andreas Wolf¹ — ¹Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — ²Weizman Institute of Science, Rehovot, 76100, Israel

The electrostatic Cryogenic Trap for Fast ion beams (CTF) employed the already demonstrated extremely high vacuum (room temperature equivalent pressure of 8 · 10⁻¹⁴ mbar or a residual gas density around 2000 cm⁻³) to investigate ion bunching properties. Since the main ion loss processes are dramatically reduced at these residual gas pressures, beam lifetimes of over 5 minutes were measured. Coherent ion bunches were observed for tens of seconds, demonstrating a dramatic increase from previous measurements using room-temperature electrostatic ion beam traps (EIBTs) with durations of around 100 ms. The observed decays demonstrate that a minimum charge density is required to sustain the bunch. Both N₂⁺ and Al₂⁻ ion bunches stored at energies between 6.0 and 7.1 keV demonstrate qualitatively similar decays. These ion bunch decays in addition to a determination of the initial bunch shape using a laser probing technique will be presented. The implications of these bunch decays for using EIBTs as mass spectrometers will also be discussed.