Numerical Modeling on Thermal Loading of Diamond Crystal in X-ray FEL Oscillator

TL;DR

This study systematically models the thermal effects on diamond crystals used in X-ray FEL oscillators, showing that with proper design, their performance remains robust despite heating.

Contribution

It introduces a combined simulation approach using Geant4 and ANSYS to analyze thermal loading effects on diamond crystals in X-ray FELs, highlighting key dependencies.

Findings

Thermal loading impacts are significant but manageable with optimized design.

X-ray FEL oscillators remain robust under thermal effects.

Environmental temperature, crystal size, and pulse parameters influence thermal stress.

Abstract

Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono$-$chromator in the next generation of free electrons lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design.