A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions
Abstract
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
- Authors:
-
- Jefferson Lab, Newport News, VA
- Brookhaven National Lab, Upton, NY
- Publication Date:
- Research Org.:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- OSTI Identifier:
- 1221879
- Report Number(s):
- JLAB-ACC-15-2066; DOE/OR/23177-3535
- DOE Contract Number:
- AC05-84ER40150
- Resource Type:
- Conference
- Resource Relation:
- Conference: IPAC 2015, 3-8 May 2015. Richmond, Virginia
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS
Citation Formats
Benson, Stephen V., Douglas, David R., Tennant, Christopher D., Wilson, Frederick G., and Nguyen, Dinh. A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions. United States: N. p., 2015.
Web.
Benson, Stephen V., Douglas, David R., Tennant, Christopher D., Wilson, Frederick G., & Nguyen, Dinh. A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions. United States.
Benson, Stephen V., Douglas, David R., Tennant, Christopher D., Wilson, Frederick G., and Nguyen, Dinh. 2015.
"A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions". United States. https://www.osti.gov/servlets/purl/1221879.
@article{osti_1221879,
title = {A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions},
author = {Benson, Stephen V. and Douglas, David R. and Tennant, Christopher D. and Wilson, Frederick G. and Nguyen, Dinh},
abstractNote = {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},
doi = {},
url = {https://www.osti.gov/biblio/1221879},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Sep 01 00:00:00 EDT 2015},
month = {Tue Sep 01 00:00:00 EDT 2015}
}