Study of inner-shell vacancy cascades by coincidence techniques
Abstract
An inner-shell vacancy in an atom decays by an intricate combination of Auger and fluorescence processes. The interrelation between these processes is not well understood because traditional studies of core-excited atoms focus on only one of the many particles that participate in the relaxation - largely ignoring the other components and the correlations between them. To understand these correlations we developed a coincidence technique that uses coincident detection of X-rays and electrons to select decay pathways that involve emission of both an X-ray photon and electrons. In the first application of this technique, the Ar 1s photoelectron spectrum was recorded selectively in coincidence with X-ray fluorescence to eliminate the asymmetric broadening and shifting of the energy distribution which results due to post-collision interaction with K-Auger electrons. This allowed the direct observation of the interaction between the photoelectron and the decay of core holes created after the initial photoionization event. We have also applied this technique to the much more complex problem of understanding Auger-electron spectra produced by vacancy cascades following inner-shell excitation. For example, we previously recorded non-coincident electron spectra of L{sub 2,3}MM Auger transitions following K-shell excitation of argon. Interpretation of these spectra is difficult because they are complicatedmore »
- Authors:
- Publication Date:
- Research Org.:
- Argonne National Lab., IL (United States)
- OSTI Identifier:
- 166504
- Report Number(s):
- ANL-95/14
ON: DE96000985; TRN: 95:007970-0220
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: Aug 1995; Related Information: Is Part Of Physics Division Annual Report, April 1, 1994--March 31, 1995; Henning, W.F.; PB: 207 p.
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 66 PHYSICS; 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; INNER-SHELL EXCITATION; COINCIDENCE METHODS; PROGRESS REPORT; X-RAY FLUORESCENCE ANALYSIS; PHOTOIONIZATION
Citation Formats
LeBrun, T., Arp, U., MacDonald, M., and Southworth, S.H.. Study of inner-shell vacancy cascades by coincidence techniques. United States: N. p., 1995.
Web. doi:10.2172/166504.
LeBrun, T., Arp, U., MacDonald, M., & Southworth, S.H.. Study of inner-shell vacancy cascades by coincidence techniques. United States. doi:10.2172/166504.
LeBrun, T., Arp, U., MacDonald, M., and Southworth, S.H.. Tue .
"Study of inner-shell vacancy cascades by coincidence techniques". United States.
doi:10.2172/166504. https://www.osti.gov/servlets/purl/166504.
@article{osti_166504,
title = {Study of inner-shell vacancy cascades by coincidence techniques},
author = {LeBrun, T. and Arp, U. and MacDonald, M. and Southworth, S.H.},
abstractNote = {An inner-shell vacancy in an atom decays by an intricate combination of Auger and fluorescence processes. The interrelation between these processes is not well understood because traditional studies of core-excited atoms focus on only one of the many particles that participate in the relaxation - largely ignoring the other components and the correlations between them. To understand these correlations we developed a coincidence technique that uses coincident detection of X-rays and electrons to select decay pathways that involve emission of both an X-ray photon and electrons. In the first application of this technique, the Ar 1s photoelectron spectrum was recorded selectively in coincidence with X-ray fluorescence to eliminate the asymmetric broadening and shifting of the energy distribution which results due to post-collision interaction with K-Auger electrons. This allowed the direct observation of the interaction between the photoelectron and the decay of core holes created after the initial photoionization event. We have also applied this technique to the much more complex problem of understanding Auger-electron spectra produced by vacancy cascades following inner-shell excitation. For example, we previously recorded non-coincident electron spectra of L{sub 2,3}MM Auger transitions following K-shell excitation of argon. Interpretation of these spectra is difficult because they are complicated and consist of many overlapping or unresolved Auger transitions between different ionic states.},
doi = {10.2172/166504},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 01 00:00:00 EDT 1995},
month = {Tue Aug 01 00:00:00 EDT 1995}
}
-
Argon L{sub 2.3}-M{sub 2.3}M{sub 2.3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons.
-
A STUDY OF THE INTERNAL FIELDS ACTING ON NUCLEI IN SOLIDS USING THE TECHNIQUES OF THE MOSSBAUER ABSORPTION AND PERTURBATION OF *gamma/-*gamma/CASCADES. Annual Summary Report, January 1, 1961-December 31, 1961
Study of the internal fields acting on nuclei in solids is being carried out using Mossbauer absorption and perturbations of gamma - gamma cascades. gamma - gamma correlation experiments using Eu/sup 152/ decaying to Sm/sup 152/ show a temperature dependence of the attenuation coefficients of the correlation, justifying assumption of time dependent perturbations. Rotation of the corre1ation pattern from Eu/sup 152/ decay in an external magnet field is noted to be also temperature dependent. For Tb/sup 160/ in an external transverse field an angle of rotation of 85 deg in the negative direction is found as predicted, and an attenuationmore » -
Proposal to Study Electroproduction with Coincidence Techniques at High Energies
Using the large aperture spectrometer of proposal 144 and the electron beam with the tagging system removed we propose to study deep inelastic electron scattering at incident electron energies between 50 and 150 GeV, for values of q{sup 2} between 1 and 20 Gev{sup 2}/c and {nu} between 10 and 130 GeV. The spectrometer will detect not only the scattered electron but also most of the secondary particles.