Abstract
Using a grazing emission method, we have made measurements of 22.6-GeV electron impact ionization cross sections at the front and back faces of ∼ 70-µm thick Al and Cu foils. These give, respectively, the cross sections without and with a density effect predicted by Fermi. For Cu, the back cross section ratio at 22.6 and 5.1 GeV (previously measured) is 1.00±0.04, confirming the predicted energy independence of this cross section. The absolute cross sections agree overall with theoretical calculations.
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Spooner, D.W., Meyerhof, W.E., Kuffner, J.J. et al. Density effect in relativistic K-shell ionization. Z Phys D - Atoms, Molecules and Clusters 29, 265–268 (1994). https://doi.org/10.1007/BF01437845
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DOI: https://doi.org/10.1007/BF01437845