Eur. Phys. J. C (2025) 85: 682
https://doi.org/10.1140/epjc/s10052-025-14415-3

Regular Article - Experimental Physics

Evolution of high-energy positron ionization loss spectra in a silicon crystal with the change of its orientation from axial to planar

¹ Akhiezer Institute for Theoretical Physics, National Science Center “Kharkiv Institute of Physics and Technology”, Akademichna Str., 1, 61108, Kharkiv, Ukraine
² V.N. Karazin Kharkiv National University, Svobody Sq. 4, 61022, Kharkiv, Ukraine

^a strofymenko@gmail.com

Received: 20 February 2025
Accepted: 10 June 2025
Published online: 21 June 2025

Abstract

On the basis of computer simulation, the ionization energy loss distributions (spectra) of high-energy positrons impinging on a silicon crystal at various angles $\psi$ with respect to the axis $⟨100⟩$ are considered. The method of simulation of high-energy particle ionization loss in oriented crystals is presented in detail. It is demonstrated that along with the probability of particle close collisions with atoms, the probability of distant collisions can be also sensitive to the particle position in the crystal lattice. Evolution of the ionization loss spectra with the change of crystal orientation relative to the incident particle momentum from the axial $⟨100⟩$ to the planar (100) and (110) with the increase of $\psi$ is investigated. It is shown that in the transition $⟨100⟩\to (100)$ the most probable energy loss $E_{\mathrm{MP}}$ experiences a sharp maximum and discontinuity, while in the transition $⟨100⟩\to (110)$ the amplitude of its variation is much smaller. Behavior of the average restricted energy loss $E_{\mathrm{AV}}$ in these transitions is investigated as well. Correlation of the dependences of $E_{\mathrm{MP}}$ and $E_{\mathrm{AV}}$ on $\psi$ with the change of the particle motion regime is discussed.