Title :
Longitudinal density modulation of unstable bunches emitting coherent IR
Author :
Podobedov, B. ; Carr, G.L. ; Kramer, S.L. ; Murphy, J.B.
Author_Institution :
Nat. Synchrotron Light Source, Brookhaven Nat. Lab., Upton, NY, USA
Abstract :
Observations of coherent infrared (IR) light emissions from ~30 cm long electron bunches at the NSLS VUV ring have been reported. The emissions occurred above some current threshold and had a maximum spectral content near 42 GHz, leading to speculations that they were due to a longitudinal instability creating a ~7 mm modulation of the bunch density. To check this experimentally we performed streak camera measurements recording a large number of beam profiles taken both during and between the coherent emission bursts. In the course of our studies we have directly proven that the longitudinal beam density indeed experiences a significant modulation when coherent emission bursts occur
Keywords :
X-ray production; electron accelerators; electron beams; infrared sources; particle beam bunching; particle beam diagnostics; particle beam extraction; storage rings; streak cameras; 30 cm; 42 GHz; NSLS VUV ring; beam profiles; bunch density; coherent emission; coherent emission bursts; coherent infrared light emission; current threshold; long electron bunches; longitudinal beam density; longitudinal density modulation; longitudinal instability; maximum spectral content; streak camera measurements; synchrotron radiation source; unstable bunches; Bandwidth; Cameras; Frequency; Laboratories; Light sources; Optical modulation; Performance evaluation; Shape measurement; Signal detection; Synchrotrons;
Conference_Titel :
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-7191-7
DOI :
10.1109/PAC.2001.987228
