Corrugated structure insertion for extending the SASE bandwidth up to 3% at the European XFEL

TL;DR

This paper demonstrates that inserting corrugated structures into the European XFEL can significantly increase the radiation bandwidth up to 3%, enabling more efficient femtosecond nanocrystallography by broadening the XFEL spectrum.

Contribution

The study introduces an analytical modal model of the wake function in corrugated structures and shows through simulations that they can extend the XFEL bandwidth to 3%.

Findings

Bandwidth increased to 3% with corrugated structures.

Achieved femtosecond pulse duration at 5.4 keV.

Potential for improved nanocrystallography data collection.

Abstract

The usage of x-ray free electron laser (XFEL) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation. Hence a wide radiation bandwidth will be useful in order to obtain and to index a larger number of Bragg peaks used for determination of the crystal orientation. Considering the baseline configuration of the European XFEL in Hamburg, and based on beam dynamics simulations, we demonstrate here that the usage of corrugated structures allows for a considerable increase in radiation bandwidth. Data collection with a 3% bandwidth, a few microjoule radiation pulse energy, a few femtosecond pulse duration, and a photon energy of 5.4 keV is possible. For this study we have developed an analytical modal representation of the short-range wake function of the flat corrugated structures for arbitrary offsets of the source and the witness particles.