Soft x-ray free electron laser microfocus for exploring matter under extreme conditions.

Journal article

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 microJ, 5 Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) - PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of < or =1 microm. Observations were correlated with simulations of best focus to provide further relevant information.

Authors: Nelson, A; Toleikis, S; Chapman, H; Bajt, S; Krzywinski, J

• Publication status: Published
• Publisher: Optical Society of American (OSA)
• Journal: Optics express
• Volume: 17
• Issue: 20
• Pages: 18271-18278
• Publication date: 2009-09-01
• DOI: 10.1364/oe.17.018271
• EISSN: 1094-4087
• ISSN: 1094-4087
• Language: English
• Keywords: Equipment Failure Analysis; Materials Testing; X-Ray Diffraction; Reproducibility of Results; Lenses; Equipment Design; Computer-Aided Design; Lasers; Electrons; Sensitivity and Specificity