FEL2011 - List of Authors (Brachmann, A.)

Paper	Title	Page
WEPA06	Experimental Studies with Spatial Gaussian-cut Laser for the LCLS Photocathode Gun	341
	F. Zhou, A. Brachmann, P. Emma, A. Gilevich, Z. Huang SLAC, Menlo Park, California, USA
	Funding: U.S. Department of Energy under contract DE-AC02-76SF00515 To further enhance the LCLS injector performances or simplify its operating conditions, we are evaluating the various parameters including the photocathode drive laser. Simulations show that both the projected and time-sliced emittances with spatial Gaussian profiles having reasonable tail-cutoff are better than those with uniform one. The simulated results are also supported by theoretical analyses. In the LCLS, the spatial uniform or quasi-Gaussian laser profiles are conveniently obtained by adjusting the optics of telescope upstream of an iris, used to define laser size on the cathode. Preliminary beam studies at the LCLS show that both the projected and time-sliced emittances with spatial quasi-Gaussian laser are almost as good as, although not better than, those with uniform one, and also laser transmission through the iris with the quasi-Gaussian is twice that with uniform one, which is to ease copper cathode operations and thus improve the LCLS operation efficiency. More beam studies are planned in the coming summer to measure FEL performances with the quasi-Gaussian in comparison with the uniform one. All simulations and measurements are presented.

Paper

Title

Page

Experimental Studies with Spatial Gaussian-cut Laser for the LCLS Photocathode Gun

341

F. Zhou, A. Brachmann, P. Emma, A. Gilevich, Z. Huang
SLAC, Menlo Park, California, USA

Funding: U.S. Department of Energy under contract DE-AC02-76SF00515
To further enhance the LCLS injector performances or simplify its operating conditions, we are evaluating the various parameters including the photocathode drive laser. Simulations show that both the projected and time-sliced emittances with spatial Gaussian profiles having reasonable tail-cutoff are better than those with uniform one. The simulated results are also supported by theoretical analyses. In the LCLS, the spatial uniform or quasi-Gaussian laser profiles are conveniently obtained by adjusting the optics of telescope upstream of an iris, used to define laser size on the cathode. Preliminary beam studies at the LCLS show that both the projected and time-sliced emittances with spatial quasi-Gaussian laser are almost as good as, although not better than, those with uniform one, and also laser transmission through the iris with the quasi-Gaussian is twice that with uniform one, which is to ease copper cathode operations and thus improve the LCLS operation efficiency. More beam studies are planned in the coming summer to measure FEL performances with the quasi-Gaussian in comparison with the uniform one. All simulations and measurements are presented.