Device for source position stabilization and beam parameter monitoring at inverse Compton X-ray sources

Device for source position stabilization and beam parameter monitoring at inverse Compton X-ray sources

Citation

Günther, B., Dierolf, M., Achterhold, K. & Pfeiffer, F. (2019). Device for source position stabilization and beam parameter monitoring at inverse Compton X-ray sources. J. Synchrotron Rad. 26, 1278–1285. 

Keywords

  • Inverse Compton X-ray sources
  • Beam-position monitor (XBM)
  • Active source position stabilization
  • CCD camera
  • Knife edge
  • Source position drift
  • X-ray flux
  • Compact Light Source (CLS) 

Brief

The article presents a new X-ray beam monitoring and stabilization system designed for compact X-ray sources based on inverse Compton scattering. The system uses a small knife edge and a customized CCD camera to monitor the X-ray source position, size, and flux, enabling active stabilization of the source position. This active stabilization significantly reduces source position drifts, improving the stability of compact X-ray sources and making them suitable for position-sensitive experiments.

Summary

The instability of inverse Compton X-ray sources poses a challenge, especially for sensitive experiments like scanning microscopy and phase contrast imaging. This article, published in the Journal of Synchrotron Radiation, describes a beam-position monitor (XBM) designed to address this problem. Here's how it works:

  • The XBM uses a small knife edge and a CCD camera to track the X-ray source's position, size, and flux in real-time. This setup allows the XBM to operate during experiments without interfering with them.
  • The XBM feeds data into a closed-loop feedback system that adjusts the laser beam's steering to maintain a stable source position. The feedback system corrects for drifts as small as 0.05 mm, which is smaller than the XBM's measurement accuracy of 0.3-0.4 mm.
  • This approach resulted in a significant improvement in source stability. Without the XBM, the source position drifted by up to 9 mm over 3 hours. With the XBM and feedback system active, the drift was reduced to less than 1 mm over the same period, marking an improvement by an order of magnitude.

The authors suggest that this stabilization method could be applied to other X-ray sources beyond inverse Compton sources as long as the source has adjustable elements like electron beam optics or motorized laser beam optics.

Origin: https://journals.iucr.org/s/issues/2019/05/00/yi5067/yi5067.pdf

 

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