Experimental determinations of K-shell ionization cross sections of Al, Ti, Cu and L-shell characteristic X-ray production cross sections of Cu, Ag and Au (Lα, Lb and Lꝩ subshells for Au) by electron impact at incident energies of 5-27 keV are presented. Thin films of the studied elements deposited on thin carbon substrates were employed as targets in the experiments. The thickness of the thin carbon substrate was 7 μg/cm<sup>2</sup>, and the targets and their thickness values were Al (5.5 μg/cm<sup>2</sup>), Ti (28 μg/cm<sup>2</sup>), Cu (35.5 μg/cm<sup>2</sup>), Ag (44 μg/cm<sup>2</sup>) and Au (44 μg/cm<sup>2</sup>), respectively. The target thickness values were checked by using Rutherford Backscattering Spectrometry (RBS). The electron beam was provided by a scanning electron microscope (KYKY-2800B). The characteristic X-rays produced were registered by a silicon drifted detector (XR-100SDD, Amptek), which has a C2 ultrathin window and can detect the low-energy X-rays down to boron Kα line (0.183 keV). The detector's efficiency was calibrated using the standard sources (<sup>55</sup>Fe, <sup>57</sup>Co, <sup>137</sup>Cs and <sup>241</sup>Am) for X-ray energies larger than 3.3 keV and using the characteristic peak method (i.e., measuring characteristic X-ray spectra produced by 20 keV electron impact on various thick solid targets) for X-ray energies less than 3.3 keV. The experimental results were corrected by the Monte Carlo code PENELOPE for the effects of target structure and Faraday cup. Meanwhile, the electron escape rates from the Faraday cup and the signal pile-up effect were also considered. The results show that when the incident electron energy is low, the influences of electron energy loss and target thickness are significant. The thinner the targets are, the smaller the corrections are. Experimental uncertainties for K-shell ionization cross sections of Al, Ti and Cu are about 5.0%, 5.6% and 5.1%, respectively; experimental uncertainties for L-shell X-ray production cross sections for Cu and Ag are about 5.3% and 4.0%, and for Lα、L<teshuzifu>b、Lꝩ of Au are about 6.1%, 8.9% and 11.0%, respectively. The experimental L-shell characteristic X-ray production cross sections of Cu are given for the first time. Compared to the theoretical values of the semi-relativistic distorted-wave Born approximation (DWBA), most of the experimental values in this paper are in good agreement within 7% deviation. The best agreement between the experimental results and the theoretical values is obtained for the K shell ionization cross sections of Al, and the deviation is less than 1.7% for the data where the incident energies are above 10 keV. The least consistency with the theoretical values is the experimental L shell characteristic X-ray production cross sections of Cu, with a deviation of about 5-22%. The comparison of the experimental L shell characteristic X-ray production cross sections of Cu (including Ga and As elements) with DWBA theory indicates that the theoretical calculation of L shell ionization cross sections of medium heavy elements and the corresponding atomic parameters (such as fluorescence yields and Coster-Kronig transition probabilities) need to be more accurately determined. According to the present results, the ionization cross sections or characteristic X-ray production cross sections measured by the thin target thin substrate, the thin target thick substrate and the thick target methods are equivalent within the uncertainties.
