Application of Doppler Broadened Annihilation-Gamma Spectroscopy to extract elemental composition of topmost-atomic layers of external and internal surfaces
ORAL
Abstract
S. Lotfimarangloo, V. A. Chirayath, J. Driscoll, B. Wallace, R.W. Gladen, A. J. Fairchild, P.A. Sterne, A. R. Koymen and A. H. Weiss
Previous investigations by Asoka-Kumar et al. [1] has shown that the analysis of the high energy region of the Doppler broadened annihilation gamma spectrum (DBG) can be used to identify the elemental composition at the site of positron annihilation inside the bulk of the samples. Our recent results suggests that a similar analysis of the Doppler broadened annihilation gamma originating from the annihilation of surface trapped positrons may provide the surface chemical composition with the selectivity and sensitivity comparable to that of Positron Annihilation Induced Auger electron spectroscopy. Here we present experimental details and preliminary results from ongoing measurements in which DBGS data is obtained from the annihilation of positrons deposited at eV energies on clean and adsorbate covered elemental surfaces and compared with simultaneously collected positron annihilation induced Auger electron spectroscopic (PAES) from the same surfaces. This comparison will be used in the determination of the elemental sensitivity and specificity of the DBGS technique as applied to surface analysis.
[1] P. Asoka-Kumar, et al. Phys. Rev. Lett. 77 (1996) 2097.
Previous investigations by Asoka-Kumar et al. [1] has shown that the analysis of the high energy region of the Doppler broadened annihilation gamma spectrum (DBG) can be used to identify the elemental composition at the site of positron annihilation inside the bulk of the samples. Our recent results suggests that a similar analysis of the Doppler broadened annihilation gamma originating from the annihilation of surface trapped positrons may provide the surface chemical composition with the selectivity and sensitivity comparable to that of Positron Annihilation Induced Auger electron spectroscopy. Here we present experimental details and preliminary results from ongoing measurements in which DBGS data is obtained from the annihilation of positrons deposited at eV energies on clean and adsorbate covered elemental surfaces and compared with simultaneously collected positron annihilation induced Auger electron spectroscopic (PAES) from the same surfaces. This comparison will be used in the determination of the elemental sensitivity and specificity of the DBGS technique as applied to surface analysis.
[1] P. Asoka-Kumar, et al. Phys. Rev. Lett. 77 (1996) 2097.
*NSF CHE 2204230; Prepared with the aid of LLNL under Contract DE-AC52-07NA27344.
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Presenters
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Sima Lotfimarangloo
- University of Texas at Arlington