Theory and simulation of high-brightness electron beam production from laser-irradiated photocathodes in the presence of dc and rf electric fields

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5626983

Jones, M E; Peter, W

To take advantage of properties of laser-controlled photodiodes to produce electron beams, a new set of diode design criteria are needed. An analytical and numerical study of the geometrical and temporal factors that affect the design of high-brightness electron beams is presented. This study extends our previous work on this concept to include the effects of laser pulse shape, and emittance effects in the presence of rf fields. In general, the diode will not be space-charge limited. Therefore, the conventional Pierce electrode shapes are not appropriate. Furthermore, the finite temporal profile of the electron beams introduces a time-dependent space charge into the design problem. The approach taken here to minimize the emittance growth from the temporal profile of the space charge is to operate at low perveance. To obtain high currents, large electric fields are required. We exploit the fact that the electron emission is controlled by the laser and is independent of the voltage on the diode. The diode can then be driven by an rf field. In principle, operating at higher frequency allows higher breakdown limits, so the perveance can be made very small. However, operating at too high an rf frequency introduces other detrimental effects.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5626983
• Report Number(s): LA-UR-86-1941; CONF-860665-7; ON: DE86012384
• Resource Relation: Conference: 6. international conference on high power particle beams, Kobe, Japan, 9 Jun 1986; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
BEAM PRODUCTION
PHOTOCATHODES
ELECTRON BEAMS
COMPUTERIZED SIMULATION
ELECTRIC FIELDS
LASER RADIATION
RADIOWAVE RADIATION
BEAMS
CATHODES
ELECTRODES
ELECTROMAGNETIC RADIATION
LEPTON BEAMS
PARTICLE BEAMS
RADIATIONS
SIMULATION
430300* - Particle Accelerators- Auxiliaries & Components