Soft x-rays with Orbital Angular Momentum for resonant scattering experiments at the SOLEIL synchrotron

TL;DR

This paper describes the development of a new setup at SOLEIL synchrotron for generating and measuring twisted soft x-ray beams with orbital angular momentum, enabling advanced resonant scattering experiments.

Contribution

It introduces two methods for producing and assessing twisted x-ray beams and demonstrates their application in initial resonant scattering experiments at SOLEIL.

Findings

Successful implementation of spiral zone plates and fork gratings for orbital angular momentum control.

First resonant scattering experiments with twisted x-rays at SOLEIL.

Potential for future advanced scattering measurements using twisted x-ray beams.

Abstract

The paper presents a comprehensive description of a new setup implemented and commissioned at the SEXTANTS beamline of the SOLEIL synchrotron for absorption and scattering experiments with x-ray beams carrying an orbital angular momentum, also known as twisted x-ray beams. Two alternative methods have been implemented, based on the use of either spiral zone plates or fork gratings devices, and we show how they can be used for both defining and assessing the orbital angular momentum of an x-ray beam. We show also how multiple devices can be used in sequence to define an integer arithmetic of the orbital angular momentum of the final x-ray beam. Finally, we report the results of the first resonant scattering pilot experiments in transmission and reflection mode, intended to assess the feasibility of future users measurements. The availability of twisted soft x-rays complements the range of experimental techniques in elastic, resonant and coherent scattering available at the SEXTANTS beamline of the SOLEIL synchrotron.