Feasibility study of thin films deposited on a self-supporting carbon grid substrate target on the measurement of atomic inner-shell ionization cross-sections impacted by 3-30 keV electrons

摘要

In this paper, we have measured the L-alpha, L-beta and M-alpha beta X-ray production cross-sections of the W element and the K-shell ionization cross-sections of the Al element impacted by 3-30 keV electrons. A new kind of target consisting of a thin film deposited on a self-supporting carbon grid substrate has been used in this work. The self-supporting carbon grid substrate is made of several layers of super-aligned carbon nanotube arrays (the mass thickness of each layer of superaligned carbon nanotube arrays is 20 mu g/cm(2)). As a comparison, three kinds of targets consisting of a) the studied element deposited onto four layers of super-aligned carbon nanotube arrays and separated from each other by one layer of single carbon atoms, b) the studied element deposited directly onto four layers of super-aligned carbon nanotube arrays, and c) the studied element deposited directly onto two layers of super-aligned carbon nanotube arrays, were respectively prepared to figure out which type is fit for the measurement of inner-shell ionization cross-sections induced by 3-30 keV electrons. The experimental data are compared with the distorted-wave Born approximation (DWBA) theoretical predictions and with the available experimental data from other references. The results show that the first and the second targets are both suitable for the inner-shell ionization cross-section measurements by 3-30 keV electrons, but the third target is not. Besides, we present the M-shell X-ray production cross-sections of the W element by 5-30 keV electrons in this paper for the first time. Copyright (C) EPLA, 2017