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Title: Rutherford backscattering measurements at medium energies using a pulsed beam time-of-flight system

Abstract

Helium ion Rutherford backscattering is a useful method of determining the depth distributions of heavy elements in lighter substrates and, in conjunction with ion channeling. Here, the authors emphasize a pulsed time-of-flight (TOF) system for medium-energy (50 to 140 keV) Rutherford backscattering spectroscopy. A particular advantage of this approach is that X rays produced by the pulsed beam are detected by the microchannel plate detector to give an almost exact time at which the beam pulse strikes the target. This allows a reference point of time zero to be determined so that the drift times of the backscattered particles may be precisely measured. Beam pulses are formed by deflection of the ion beam using a 10-ns rise time pulse generator that provides a 0 to 100-V square wave output. This voltage is applied to deflection plates to sweep the ion beam across a 3-mm collimator. Nanosecond beam pulses have been obtained that have resulted in an energy resolution of 1.3 keV for 100-keV He ions scattered from As. This energy resolution is significantly better than the 7 keV that can be obtained using a silicon detector and results in a depth resolution for As in Si of 13 {angstrom} atmore » a backscattered angle of 150 deg and a target tilt angle of 40 deg. The detection efficiency of the microchannel plate detector for 100-keV He has been measured to be close to the fill factor of 55%. The depth profile of a 1-keV As implant in Si to a fluence of approximately 1 {times} 10{sup 15}/cm{sup 2} was measured using a 100-keV He ion beam both at normal incidence and at a target tilt angle of 40 deg. The general agreement of the experimental measurements with the results from the TRIM code is very good.« less

Authors:
; ; ;  [1];  [2]
  1. Texas A and M Univ., College Station, TX (United States)
  2. Los Alamos National Lab., NM (United States)
Publication Date:
OSTI Identifier:
678121
Report Number(s):
CONF-990605-
Journal ID: TANSAO; ISSN 0003-018X; TRN: 99:009106
Resource Type:
Journal Article
Journal Name:
Transactions of the American Nuclear Society
Additional Journal Information:
Journal Volume: 80; Conference: 1999 annual meeting of the American Nuclear Society (ANS), Boston, MA (United States), 6-10 Jun 1999; Other Information: PBD: 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; ION SCATTERING ANALYSIS; RUTHERFORD SCATTERING; BACKSCATTERING; HELIUM IONS; TIME-OF-FLIGHT METHOD; X-RAY DETECTION; ARSENIC; SILICON; ION IMPLANTATION; DEPTH

Citation Formats

Hart, R.R., Lansrud, B.D., Thompson, K.G., Tissot, P.E., and Foster, L.A. Rutherford backscattering measurements at medium energies using a pulsed beam time-of-flight system. United States: N. p., 1999. Web.
Hart, R.R., Lansrud, B.D., Thompson, K.G., Tissot, P.E., & Foster, L.A. Rutherford backscattering measurements at medium energies using a pulsed beam time-of-flight system. United States.
Hart, R.R., Lansrud, B.D., Thompson, K.G., Tissot, P.E., and Foster, L.A. Wed . "Rutherford backscattering measurements at medium energies using a pulsed beam time-of-flight system". United States.
@article{osti_678121,
title = {Rutherford backscattering measurements at medium energies using a pulsed beam time-of-flight system},
author = {Hart, R.R. and Lansrud, B.D. and Thompson, K.G. and Tissot, P.E. and Foster, L.A.},
abstractNote = {Helium ion Rutherford backscattering is a useful method of determining the depth distributions of heavy elements in lighter substrates and, in conjunction with ion channeling. Here, the authors emphasize a pulsed time-of-flight (TOF) system for medium-energy (50 to 140 keV) Rutherford backscattering spectroscopy. A particular advantage of this approach is that X rays produced by the pulsed beam are detected by the microchannel plate detector to give an almost exact time at which the beam pulse strikes the target. This allows a reference point of time zero to be determined so that the drift times of the backscattered particles may be precisely measured. Beam pulses are formed by deflection of the ion beam using a 10-ns rise time pulse generator that provides a 0 to 100-V square wave output. This voltage is applied to deflection plates to sweep the ion beam across a 3-mm collimator. Nanosecond beam pulses have been obtained that have resulted in an energy resolution of 1.3 keV for 100-keV He ions scattered from As. This energy resolution is significantly better than the 7 keV that can be obtained using a silicon detector and results in a depth resolution for As in Si of 13 {angstrom} at a backscattered angle of 150 deg and a target tilt angle of 40 deg. The detection efficiency of the microchannel plate detector for 100-keV He has been measured to be close to the fill factor of 55%. The depth profile of a 1-keV As implant in Si to a fluence of approximately 1 {times} 10{sup 15}/cm{sup 2} was measured using a 100-keV He ion beam both at normal incidence and at a target tilt angle of 40 deg. The general agreement of the experimental measurements with the results from the TRIM code is very good.},
doi = {},
journal = {Transactions of the American Nuclear Society},
number = ,
volume = 80,
place = {United States},
year = {1999},
month = {9}
}