A cantilevered liquid‐nitrogen‐cooled silicon mirror for the Advanced Light Source Upgrade. (11th August 2020)

• Record Type: Journal Article
• Authors: Cutler, Grant; Cocco, Daniele; DiMasi, Elaine; Morton, Simon; Sanchez del Rio, Manuel; Padmore, Howard
• Is Part Of: Journal of synchrotron radiation. Volume 27:Part 5(2020)
• Page Start: 1131
• Page End: 1140
• Publication Date: 2020-08-11
• Subjects: cantilevered mirrors -- wavefront propagation -- cryogenics -- silicon mirrors -- liquid‐nitrogen cooling -- high heat‐load; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577520008930
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : A cantilevered liquid‐nitrogen‐cooled silicon mirror is described that will achieve diffraction‐limited performance even under extreme power density. This mirror will serve as a robust first optic for the high‐brightness undulator beamlines at the upgraded Advanced Light Source. Abstract : This paper presents a novel cantilevered liquid‐nitrogen‐cooled silicon mirror design for the first optic in a new soft X‐ray beamline that is being developed as part of the Advanced Light Source Upgrade (ALS‐U) (Lawrence Berkeley National Laboratory, USA). The beamline is optimized for photon energies between 400 and 1400 eV with full polarization control. Calculations indicate that, without correction, this design will achieve a Strehl ratio greater than 0.85 for the entire energy and polarization ranges of the beamline. With a correction achieved by moving the focus 7.5 mm upstream, the minimum Strehl ratio is 0.99. This design is currently the baseline plan for all new ALS‐U insertion device beamlines.