Share Email Print

Proceedings Paper

Simple x-ray focusing mirror using float glass
Author(s): Zhijian Yin; Lonny E. Berman; Steve B. Dierker; Eric Dufresne; D. Peter Siddons
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

In our recent x-ray photon correlation spectroscopy (speckle) experiments at NSLS, one of the challenges is to increase the coherent photon flux through a pinhole, whose size is chosen to match the beam's horizontal transverse coherence length lh. We adopted an approach to vertically focus the x-ray beam so as to match its vertical transverse coherence length lv (at NSLS X13, lv approximately 50 lh, lh approximately 12 micrometers at 3 KeV) with lh. By demagnifying the vertical size by a factor of lv/lh, we expect to increase the intensity of the x-rays through the pin hole by the same factor while keeping the beam coherent. A piece of commercial 3/8' thick float glass, by virtue of its low surface roughness (approximately 3 angstroms rms), good reflectivity in the low photon energy range of interest and low cost, was chosen as the mirror material. A computer controlled motorized bender with a four point bending mechanism was designed and built to bend the float glass to a continuously variable radius of curvature from -700 m (intrinsic curvature of the glass surface) to < 300 m, measured with the Long Trace Profiler at the BNL Metrology Lab. This mirror bender assembly allows us to continuously change the focal length of the x-ray mirror down to 0.5 m under our experimental conditions. At the NSLS X13 Prototype Small Gap Undulator beamline, we were able to focus the x-ray beam from a vertical size of 0.5 mm to approximately 25 micrometers at the focal point 54 cm from the mirror center, thus increasing the photon flux density by a factor of 20. Results also show that, as expected, at an incident angle of 9 mrad, the mirror cuts off the harmonics of the undulator spectrum, leaving a clean 3 KeV fundamental for our experiments.

Paper Details

Date Published: 22 November 1996
PDF: 7 pages
Proc. SPIE 2856, Optics for High-Brightness Synchrotron Radiation Beamlines II, (22 November 1996); doi: 10.1117/12.259862
Show Author Affiliations
Zhijian Yin, Brookhaven National Lab. (United States)
Lonny E. Berman, Brookhaven National Lab. (United States)
Steve B. Dierker, Univ. of Michigan (United States)
Eric Dufresne, Univ. of Michigan (United States)
D. Peter Siddons, Brookhaven National Lab. (United States)

Published in SPIE Proceedings Vol. 2856:
Optics for High-Brightness Synchrotron Radiation Beamlines II
Lonny E. Berman; John Arthur, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?