Capillary concentrators for synchrotron radiation beamlines

Steve M. Heald, Dale L. Brewe, Kyungha H. Kim, Frederick C. Brown, Bill Barg, Edward A. Stern

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations


Capillary concentrators condense x-rays by multiple reflections down a gradually tapering capillary. They can provide sub-micron beam spots, and are promising candidates for use in the next generation x-ray microprobe beamlines. The weak energy dependence of their properties make them especially useful for energy scanning applications such as micro-XAFS. This paper examines the potential performance of capillary optics for an x-ray microprobe, as well as some practical issues such as fabrication and alignment. Best performance at third generation sources requires long capillaries, and we have been using fiber optics techniques to fabricate capillaries up to one meter in length. The performance of shorter (less than about 0.5 m) capillaries has often been found to agree well with theoretical calculations, indicating the inner surface is a high quality x-ray reflector. These capillaries have been tested at the NSLS for imaging and micro-XAFS down to 2.6 μm resolution with excellent results. On an unfocused bend magnet line flux density approaching 106 ph/sec/μm2 has been achieved. While nearly optimum profiles have been achieved for longer capillaries, the results have been disappointing, and alignment problems are suspected. The dramatic improvement in performance possible at third generation synchrotrons such as the APS is discussed along with improvements possible by using the capillaries in conjunction with coupling optics.

Original languageEnglish
Pages (from-to)36-47
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 22 Nov 1996
Externally publishedYes
EventOptics for High-Brightness Synchrotron Radiation Beamlines II 1996 - Denver, United States
Duration: 4 Aug 19969 Aug 1996

Bibliographical note

Publisher Copyright:
© 1996 SPIE. All rights reserved.


  • Micro-XAFS
  • Synchrotron radiation
  • Tapered capillary
  • X-ray imaging
  • X-ray microprobe
  • X-ray optics


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