| Issue |
J. Phys. Colloques
Volume 48, Number C9, Décembre 1987
X-Ray and Inner-Shell ProcessesVol. 1 |
|
|---|---|---|
| Page(s) | C9-487 - C9-490 | |
| DOI | https://doi.org/10.1051/jphyscol:1987978 | |
Vol. 1
J. Phys. Colloques 48 (1987) C9-487-C9-490
DOI: 10.1051/jphyscol:1987978
A SEMI-EMPIRICAL, FORMULA FOR THE TOTAL K-SHELL IONIZATION CROSS SECTION BY ELECTRON IMPACT
C. JAKOBY, H. GENZ and A. RICHTERInstitut für Kernphysik, Technische Hochschule Darmstadt, D-6100 Darmstadt, F.R.G.
Abstract
The evaluation of some 600 measurements of electron induced K-shell ionization cross sections for elements with 6 ≤ Z ≤ 92 and impact energies of IK ≤ E0 ≤ 5 GeV yielded a set of reliable data, which were used for the derivation of a semi-empirical formula, that enables the prediction of σK for al1 elements and electron bombarding energies. Based on the two-parameter Bethe formula a three-parameter formula was was derived, which depends on β and Z and the three Z-dependent constants. They are needed to describe properly position, slope and height of the cross section maximum as well as the energy behaviour. They were deduced by fitting the three-parameter formula to the evaluated data of eleven elements. Since the constants exhibit a Z dependence, a power law or polynomials were fitted to these quantities. The newly derived formula predicts the the electron induced K-shell ionization cross section for all Z and impact energies to about ± 13%.