Peak Current Optimization for LCLS Bunch Compressor 2
In this study, we calculate the effects of Coherent Synchrotron Radiation (CSR) in the LCLS bunch compression section BC2[3] on the resulting FEL performance, considering a realistic, strongly non-gaussian longitudinal charge distribution. The longitudinal chirping required for the bunch compression process leads to a non-linear, non-monotonous {delta}(z) functional dependence (Fig. 1 shows the current distribution and the energy offset along the bunch). We model this functional dependence by matching it to a cubic polynomial {delta} {approx} c{sub 0} + c{sub 1}z + c{sub 2}z{sup 2} + c{sub 3}z{sup 3}. During compression, the charge distribution in the z-{delta} plane will ''fold over'', as shown in fig. 2. This leads to a cusp at each end of the current distribution I(z), as shown in figure 3. High |l'(z)| values will lead to high longitudinal CSR fields, with possible detrimental effects on the transverse projected and slice emittance as well as energy spread, possibly affecting FEL performance.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 890839
- Report Number(s):
- SLAC-PUB-11171; TRN: US0604834
- Resource Relation:
- Conference: Presented at the 9th European Particle Accelerator Conference (EPAC 2004), Lucerne, Switzerland, 5-9 Jul 2004
- Country of Publication:
- United States
- Language:
- English
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