Damage threshold in pre-heated materials exposed to intense X-rays

TL;DR

This study models how pre-heating affects damage thresholds in various materials exposed to intense X-ray pulses, revealing that thermal damage thresholds generally decrease or stay constant with temperature, while nonthermal thresholds vary.

Contribution

It provides a theoretical analysis of damage thresholds in pre-heated materials under intense X-ray irradiation, considering both thermal and nonthermal damage mechanisms across different material classes.

Findings

Thermal damage thresholds tend to decrease or remain unchanged with increased temperature.

Nonthermal damage thresholds can either increase or decrease depending on the material.

The study uses advanced numerical techniques to simulate electronic and atomic dynamics during irradiation.

Abstract

Materials exposed to ultrashort intense x-ray irradiation may experience various damaging conditions depending on the in-situ temperature. A pre-heated target exposed to intense x-rays plays a crucial role in numerous systems of physical-technical importance, ranging from the heavily-, and repeatedly radiation-loaded optics at x-ray free-electron laser facilities, to the first wall of prospective inertial fusion reactors. We study theoretically the damage threshold dependence on the temperature in different classes of materials: an insulator (diamond), a semiconductor (silicon), a metal (tungsten), and an organic polymer (PMMA). The numerical techniques used here enable us to trace the evolution of both, an electronic state and atomic dynamics of the materials. It includes damage mechanisms such as thermal damage (induced by an increase of the atomic temperature due to energy transfer from x-ray-excited electrons) and nonthermal phase transitions (induced by changes in the interatomic potential due to excitation of electrons). We demonstrate that in the pre-heated materials, typically, the thermal damage threshold stays the same or lowers with the increase of the in-situ temperature, whereas nonthermal damage thresholds may be lowered or raised, depending on the particular material and specifics of the damage kinetics.