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An STM With A Time-Of-Flight Analyzer For Atomic Species Identification

Published online by Cambridge University Press:  02 July 2020

U. Weierstall
Affiliation:
Department of Physics and Astronomy, Arizona State University, Tempe, AZ85287. USA.
J.C.H. Spence
Affiliation:
Department of Physics and Astronomy, Arizona State University, Tempe, AZ85287. USA.
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Extract

The local chemistry of many surface reactions is unknown, since no techniques exist for identifying atom types at individual defect sites on extended crystal surfaces. An STM has therefore been constructed which allows atomic clusters of interest to be transferred into a time-of-flight spectrometer for species identification. Atoms are first transferred from the STM sample to the tip, using a small voltage pulse. The sample is then removed, and these atoms ejected into a time-of-flight (TOF) analyzer for mass identification. A 75mm flat Chevron MCP is used as TOF-detector. The output is led to a digital oscilloscope, whose trace is triggered by the tip pulse. Scope, triggering and high voltage are under Labview control, spectra are transferred into the PC and the mass to charge ratio of the ionized species is calculated. The STM has a vertical axis and is based on the Burleigh Inchworm with tube scanner for sample movement.

Type
Scanned Probe Microscopy
Copyright
Copyright © Microscopy Society of America

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References

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