Interaction of ultrashort X-ray pulses with B4C, SiC and Si

TL;DR

This study uses simulations to analyze how ultrashort X-ray pulses at 32.5 nm and 6 nm interact with B4C, SiC, and Si, focusing on ionization, opacity changes, and crater formation, with comparisons to experimental data.

Contribution

It provides a detailed simulation of ultrashort X-ray interactions with specific materials, highlighting wavelength-dependent effects on opacity and crater depth, validated against experiments.

Findings

Opacity changes are modest at 32.5 nm for B4C and Si, larger for SiC.

At 6 nm, opacity decreases significantly due to weak inverse bremsstrahlung.

Crater depth increases at 6 nm for high fluences.

Abstract

The interaction of 32.5 and 6 nm ultrashort X-ray pulses with the solid materials B4C, SiC and Si is simulated with a non-local thermodynamic equilibrium (NLTE) radiation transfer code. We study the ionization dynamics as function of depth in the material, modifications of the opacity during irradiation and estimate crater depth. Furthermore, we compare the estimated crater depth with experimental data, for fluences up to 2.2 J/cm2. Our results show that at 32.5 nm irradiation, the opacity changes with less than a factor of 2 for B4C and Si and a factor of 3 for SiC, for fluences up to 200 J/cm2. At a laser wavelength of 6 nm, the model predicts a dramatic decrease in opacity due to the weak inverse bremsstrahlung, increasing the crater depth for high fluences.