A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions
- Jefferson Lab, Newport News, VA
- Brookhaven National Lab, Upton, NY
Virtually all existing high energy (>few MeV) linac-driven FELs compress the electron bunch length though the use of off-crest acceleration on the rising side of the RF waveform followed by transport through a magnetic chicane. This approach has at least three flaws: 1) it is difficult to correct aberrations--particularly RF curvature, 2) rising side acceleration exacerbates space charge-induced distortion of the longitudinal phase space, and 3) all achromatic "negative compaction" compressors create parasitic compression during the final compression process, increasing the CSR-induced emittance growth. One can avoid these deficiencies by using acceleration on the falling side of the RF waveform and a compressor with M56>0. This approach offers multiple advantages: 1) It is readily achieved in beam lines supporting simple schemes for aberration compensation, 2) Longitudinal space charge (LSC)-induced phase space distortion tends, on the falling side of the RF waveform, to enhance the chirp, and 3) Compressors with M56>0 can be configured to avoid spurious over-compression. We will discuss this bunch compression scheme in detail and give results of a successful beam test in April 2012 using the JLab UV Demo FEL
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 1221879
- Report Number(s):
- JLAB-ACC-15-2066; DOE/OR/23177-3535
- Resource Relation:
- Conference: IPAC 2015, 3-8 May 2015. Richmond, Virginia
- Country of Publication:
- United States
- Language:
- English
Similar Records
Bunch length compression method for free electron lasers to avoid parasitic compressions
Investigation of Microbunching Instabilities in Modern Recirculating Accelerators