Turn-by-Turn Imaging of the Transverse Beam Profile in PEP-II
- Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
- Department of Physics, University of Nevada, Reno, NV 89557 (United States)
- Physics Department, California Institute of Technology, Pasadena, CA 91125 (United States)
During injection or instability, the transverse profile of an individual bunch in a storage ring can change significantly in a few turns. However, most synchrotron-light imaging techniques are not designed for this time scale. We have developed a novel diagnostic that enhances the utility of a fast gated camera by adding, inexpensively, some features of a dual-axis streak camera, in order to watch the turn-by-turn evolution of the transverse profile, in both x and y. The beam's elliptical profile is reshaped using cylindrical lenses to form a tall and narrow ellipse - essentially the projection of the full ellipse onto one transverse axis. We do this projection twice, by splitting the beam into two paths at different heights, and rotating the ellipse by 90 deg. on one path. A rapidly rotating mirror scans these vertical 'pencils' of light horizontally across the photocathode of the camera, which is gated for 3 ns on every Nth ring turn. A single readout of the camera captures 100 images, looking like a stroboscopic photograph of a moving object. We have observed the capture of injected charge into a bunch and the rapid change of beam size at the onset of a fast instability.
- OSTI ID:
- 20894929
- Journal Information:
- AIP Conference Proceedings, Vol. 868, Issue 1; Conference: 12. beam instrumentation workshop, Batavia, IL (United States), 1-4 May 2006; Other Information: DOI: 10.1063/1.2401418; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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