Initial source of microbunching instability studies in a free electron laser injector
We present the first experimental studies of the initial source of electron beam microbunching instability in a free electron laser (FEL) injector. By utilizing for the studies a transform-limited laser pulse at the photocathode, we eliminated laser-induced microbunching at the National Synchrotron Light Source Source Development Laboratory (SDL). The detailed measurements of the resulting electron beam led us to conclude that, at SDL, microbunching arising from shot noise is not amplified to any significant level, thereby allowing us to set an upper limit on the initial modulation depth of microbunching arising from shot noise. Our analysis demonstrated that the only significant source of microbunching instability under normal operational conditions at SDL is the longitudinal modulation of the photocathode laser pulse. Our work shows that assuring a longitudinally smoothed photocathode laser pulse allows mitigating microbunching instability at a typical FEL injector with a moderate microbunching gain.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1039273
- Report Number(s):
- BNL-96850-2012-JA; 39KC02000; TRN: US1202137
- Journal Information:
- Physical Review Special Topics - Accelerators and Beams, Vol. 14, Issue 11; ISSN 1098-4402
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of Microbunching Instabilities in Modern Recirculating Accelerators
Suppression of Microbunching Instability in the Linac Coherent Light Source