An in-vacuum diffractometer for resonant elastic soft x-ray scattering

TL;DR

This paper presents a detailed design and performance analysis of a specialized in-vacuum diffractometer for resonant elastic soft x-ray scattering, capable of high-precision measurements at ultra-high vacuum and low temperatures.

Contribution

It introduces a novel 4-circle in-vacuum diffractometer with multiple detectors and ultra-high vacuum operation, tailored for soft x-ray scattering studies.

Findings

Successfully measured diffraction and reflectivity in complex materials.

Achieved operation at 18 K with ultra-high vacuum conditions.

Demonstrated versatility with multiple detectors for various signal strengths.

Abstract

We describe the design, construction and performance of a 4-circle in-vacuum diffractometer for resonant elastic soft x-ray scattering and reflectivity. The diffractometer, installed on the REIXS beamline at the Canadian Light Source, includes 9 in-vacuum motions driven by in-vacuum stepper motors and operates in ultra-high vacuum at base pressure of 2 x10^-10 Torr. Cooling to a base temperature of 18 K is provided with a closed-cycle cryostat. The diffractometer includes a choice of 3 photon detectors: a photodiode, a channeltron and a 2D sensitive channelplate detector. Along with variable slit and filter options, these detectors are suitable for studying a wide range of phenomena having both weak and strong diffraction signals. Example measurements of diffraction and reflectivity in Nd-doped (La,Sr)_2CuO_4 and thin film (Ga,Mn)As are shown.