Title :
Emittance measurements for the Illinois/CEBAF polarized electron source
Author :
Dunham, B.M. ; Cardman, L.S. ; Sinclair, C.K.
Author_Institution :
Dept. of Phys., Illinois Univ., Champaign, IL, USA
Abstract :
The transverse thermal properties of the electrons photo-emitted from GaAs determine the intrinsic beam emittance, an important quantity in applications such as polarized electron sources and high-brightness sources. In this paper, emittance measurements using the Illinois/CEBAF polarized electron source are described. The emittance was measured as a function of both the laser beam spot size and laser wavelength at low currents. The data was used to infer the transverse thermal energy of the electrons photoemitted from GaAs for wavelengths between 514 and 840 nm. Near the bandgap the transverse energy is ~34 meV, a factor of 3 lower than that of the beam from a typical thermionic electron gun
Keywords :
electron accelerators; electron sources; particle beam diagnostics; particle sources; 34 meV; 514 to 840 nm; GaAs; Illinois/CEBAF polarized electron source; bandgap; electrons photoemission; emittance measurements; high-brightness sources; intrinsic beam emittance; laser beam spot size; laser wavelength; low currents; transverse thermal energy; transverse thermal properties; Current measurement; Electron beams; Electron emission; Electron sources; Gallium arsenide; Laser beams; Photonic band gap; Polarization; Size measurement; Wavelength measurement;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.505119
