A Soft X-Ray Emission Endstation for the Canadian Light Source

Abstract

Based on a previously completed design for a soft X-ray (50-1100 eV) emission spectrometer, an endstation was constructed for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline at the CLS. The optical design employed techniques and software tools developed in-house using ray-tracing and diffraction grating efficiency calculations to analyze and compare existing designs and to propose a new design with superior performance. This design employs Rowland circle geometry to achieve a theoretical resolving power in excess of 2,500 in our range of interest. In addition, a novel optical design for a larger extremely high resolution spectrometer has been completed to provide theoretical resolving powers exceeding 10,000 throughout the higher end of the spectrum. To accommodate this optical design a completely new mechanical design was required, involving significant mechanical, electrical, vacuum and software engineering. Countless custom fabricated parts were required along with numerous o -the-shelf secondary instruments and systems. All told, this entirely student-managed project has cost over $1.5M and taken over 5 years. Construction is finally complete and the endstation is currently being commissioned. Necessary design changes made during the mechanical design process resulting in the selection of a more suitable, but lower resolution, detector. This reduced the theoretical maximum resolving power to 1,800 for the first order gratings and roughly 5,000 for the third order gratings. Commissioning is still underway, but first order resolutions in the range of 1,000 - 2,000 have been recorded as have third order resolutions exceeding 4,000. Publication quality data has been collecting by members of this research group and invited external users have successfully grown and measured samples here. Two of the optical elements required rework and upon their delivery the system commissioning will be completed and peer-reviewed access will begin.