# Production and decay of K-shell hollow krypton in collisions with 52 - 197 MeV/u bare xenon ions

## TL;DR

This study measures X-ray spectra of K-shell hollow krypton atoms produced in collisions with high-energy xenon ions, revealing energy shifts, vacancy ratios, and comparing results with relativistic calculations.

## Contribution

It provides the first detailed measurements of K-shell hollow krypton atom spectra in heavy-ion collisions and compares experimental data with advanced theoretical models.

## Key findings

- Energy shifts of X-ray transitions are quantified.
- The ratio of hollow to singly ionized krypton atoms is 14-24%.
- Experimental results align with relativistic coupled channel calculations.

## Abstract

X-ray spectra of K-shell hollow krypton atoms produced in single collisions with 52 - 197 MeV/u Xe54+ ions are measured in a heavy-ion storage ring equipped with an internal gas-jet target. Energy shifts of the K{\alpha}_1,2^s, K{\alpha}_1,2^(h,s), and K\b{eta}_1,3^s transitions are obtained. Thus, the average number of the spectator L-vacancies presented during the x-ray emission is deduced. From the relative intensities of the K{\alpha}_1,2^s and K{\alpha}_1,2^(h,s) transitions, the ratio of K-shell hollow krypton to singly K-shell ionized atoms is determined to be 14 - 24%. In the considered collisions, the K-vacancies are mainly created by the direct ionization which cannot be calculated within the perturbation descriptions. The experimental results are compared with a relativistic coupled channel calculation performed within the independent particle approximation.

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Source: https://tomesphere.com/paper/1706.03460