Title :
Quantum efficiency measurements of a copper photocathode in an RF electron gun
Author :
Davis, P. ; Hairapetian, G. ; Clayton, C. ; Joshi, C. ; Hartman, S. ; Park, S. ; Pellegrini, K. ; Rosenzweig, J.
Author_Institution :
Dept. of Electr. Eng., California Univ., Los Angeles, CA, USA
Abstract :
A 4.5 MeV photocathode RF gun has been commissioned at UCLA. A photo-injector drive laser produces sub 2 ps pulses of UV (λ=266 nm) light with up to 200 μJ/pulse, and illuminates a copper cathode. The photoelectrons are accelerated to an energy of 3.5 MeV within the gun. The electron beam charge is measured as a function of laser energy using an integrating current transformer (ICT). We present measurements of quantum efficiency as a function of laser polarization for injection angles of 2° and 70° with respect to the cathode normal. At 70° incidence a 50% enhancement in quantum efficiency (>10-4 ) is observed for p-polarized light over s-polarized light
Keywords :
electron guns; electron sources; photocathodes; Cu photocathode; RF electron gun; electron beam charge; integrating current transformer; laser polarization; p-polarized light; photocathode RF gun; quantum efficiency; s-polarized light; Acceleration; Cathodes; Charge measurement; Copper; Current measurement; Electron beams; Energy measurement; Optical pulses; Pulse transformers; Radio frequency;
Conference_Titel :
Particle Accelerator Conference, 1993., Proceedings of the 1993
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-1203-1
DOI :
10.1109/PAC.1993.309524
