Photoemission using femtosecond laser pulses

Conference · Tue Oct 01 04:00:00 EDT 1991

OSTI ID:10110670

Srinivasan-Rao, T; Tsang, T; Fischer, J

Successful operation of short wavelength FEL requires an electron bunch of current >100 A and normalized emittance < 1 mm-mrad. Recent experiments show that RF guns with photocathodes as the electron source may be the ideal candidate for achieving these parameters. To reduce the emittance growth due to space charge and RF dynamics effects, the gun may have to operate at high field gradient (hence at high RF frequency) and a spot size small compared to the aperture. This may necessitate the laser pulse duration to be in the subpicosecond regime to reduce the energy spread. We will present the behavior of metal photocathodes upon irradiation with femtosecond laser beams, comparison of linear and nonlinear photoemission, and scalability to high currents. Theoretical estimate of the intrinsic emittance at the photocathode in the presence of the anomalous heating of the electrons, and the tolerance on the surface roughness of the cathode material will be discussed.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 10110670
• Report Number(s): BNL--46165; CONF-9108118--35; ON: DE92004997
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002
43 PARTICLE ACCELERATORS
430303
BEAM BUNCHING
BEAM EMITTANCE
ELECTRON GUNS
EXPERIMENTAL FACILITIES AND EQUIPMENT
FREE ELECTRON LASERS
LASERS AND MASERS
PHOTOCATHODES
PHOTOEMISSION
RF SYSTEMS
ROUGHNESS
SPACE CHARGE
SURFACES