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Title: Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters

Abstract

A design of a radio-frequency (rf) octopole ion guide with truncated conical rods arranged in a conical geometry is presented. The performance is tested in a cluster deposition apparatus used for the soft-landing of size-selected clusters on well-characterized substrates used as a model system in heterogeneous catalysis in ultrahigh vacuum. This device allows us to focus 500 pA of a mass-selected Ni{sub 20}{sup +} cluster ion beam from 9 mm down to a spot size of 2 mm in diameter. The transmittance is 70%{+-}5% at a rf voltage of 420 V{sub pp} applied over an amateur radio transceiver with an interposed homemade amplifier-transformer circuit. An increase of the cluster density by a factor of 15 has been achieved. Three ion trajectories are simulated by using SIMION6, which are relevant for this focusing device: transmitted, reflected, and absorbed. The observed effects in the simulations can be successfully explained by the adiabatic approximation. The focusing behavior of the conical octopole lens is demonstrated by experiment and simulations to be a very useful technique for increasing molecule or cluster densities on a substrate and thus reducing deposition time.

Authors:
; ; ; ; ;  [1];  [2]
  1. Lehrstuhl fuer Physikalische Chemie 1, Technical University of Munich, Lichtenbergstrasse 4, D-85748 Garching (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
20778553
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 77; Journal Issue: 1; Other Information: DOI: 10.1063/1.2162439; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADIABATIC APPROXIMATION; AMPLIFIERS; DENSITY; DESIGN; FOCUSING; GEOMETRY; HETEROGENEOUS CATALYSIS; ION BEAMS; IONS; LENSES; PERFORMANCE; RADIOWAVE RADIATION; SIMULATION; SUBSTRATES; TRAJECTORIES; TRANSFORMERS; USES

Citation Formats

Roettgen, Martin A., Judai, Ken, Antonietti, Jean-Marie, Heiz, Ueli, Rauschenbach, Stephan, Kern, Klaus, and Nanoscale Science Department, Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart. Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters. United States: N. p., 2006. Web. doi:10.1063/1.2162439.
Roettgen, Martin A., Judai, Ken, Antonietti, Jean-Marie, Heiz, Ueli, Rauschenbach, Stephan, Kern, Klaus, & Nanoscale Science Department, Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart. Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters. United States. doi:10.1063/1.2162439.
Roettgen, Martin A., Judai, Ken, Antonietti, Jean-Marie, Heiz, Ueli, Rauschenbach, Stephan, Kern, Klaus, and Nanoscale Science Department, Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart. Sun . "Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters". United States. doi:10.1063/1.2162439.
@article{osti_20778553,
title = {Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters},
author = {Roettgen, Martin A. and Judai, Ken and Antonietti, Jean-Marie and Heiz, Ueli and Rauschenbach, Stephan and Kern, Klaus and Nanoscale Science Department, Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart},
abstractNote = {A design of a radio-frequency (rf) octopole ion guide with truncated conical rods arranged in a conical geometry is presented. The performance is tested in a cluster deposition apparatus used for the soft-landing of size-selected clusters on well-characterized substrates used as a model system in heterogeneous catalysis in ultrahigh vacuum. This device allows us to focus 500 pA of a mass-selected Ni{sub 20}{sup +} cluster ion beam from 9 mm down to a spot size of 2 mm in diameter. The transmittance is 70%{+-}5% at a rf voltage of 420 V{sub pp} applied over an amateur radio transceiver with an interposed homemade amplifier-transformer circuit. An increase of the cluster density by a factor of 15 has been achieved. Three ion trajectories are simulated by using SIMION6, which are relevant for this focusing device: transmitted, reflected, and absorbed. The observed effects in the simulations can be successfully explained by the adiabatic approximation. The focusing behavior of the conical octopole lens is demonstrated by experiment and simulations to be a very useful technique for increasing molecule or cluster densities on a substrate and thus reducing deposition time.},
doi = {10.1063/1.2162439},
journal = {Review of Scientific Instruments},
number = 1,
volume = 77,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}