Simple formulae for the optimization of the FEL gain length including the effects of emittance, betatron oscillations and energy spread

Conference · Sat Aug 01 04:00:00 EDT 1992

OSTI ID:7129965

Chin, Y H

Simple analytical formulae are presented for a quick optimization of the Free Electron Laser (FEL) gain length for given values of radiation wavelength, electron beam current, normalized transverse emittance and energy spread. The optimization parameters include the gap size of the wiggler, the wiggler period and the betatron wavelength (in the case of external focusing). The method is based on the handy formulae for the FEL gain of a Gaussian beam including the effects of energy spread, emittance, and betatron oscillations of the electron beam. We have found a simple relation between the minimum FEL gain length and the optimum betatron wavelength for given energy spread, emittance, and gap size of the wiggler. When the emittance is about the radiation wavelength divided by 4{rho} and the energy spread is negligible, this relation shows that the gain length is optimized if the betatron wavelength is chosen so that the betatron phase advances by a half radian in the gain length.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7129965
• Report Number(s): LBL-32249; ESG--179; CONF-9208142--1; ON: DE92040378
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
AMPLIFICATION
BEAM CURRENTS
BEAM DYNAMICS
BEAM EMITTANCE
BEAMS
BETATRON OSCILLATIONS
CURRENTS
ELECTRICAL EQUIPMENT
ELECTROMAGNETS
ELECTRON BEAMS
EQUATIONS
EQUIPMENT
FREE ELECTRON LASERS
GAIN
LASERS
LEPTON BEAMS
MAGNETS
OPTIMIZATION
OSCILLATIONS
PARTICLE BEAMS
WIGGLER MAGNETS