2011 Particle Accelerator Conference - List of Authors (Zhao, L.)

Paper	Title	Page
WEP146	A Quasi-3D Model of Electron Cyclotron Resonance Ion Source (ECRIS)	1755
	L. Zhao, B. Cluggish, J.S. Kim Far-Tech, Inc., San Diego, California, USA
	Funding: Grant supported by DOE office of Nuclear Physics FAR-TECH, Inc is developing a hybrid, quasi-3D model to model charge breeding of an ion beam in an electron cyclotron resonance ion source. The model is a combination of 3D mapping of the plasma background calculated by GEM1D* and 3D tracking of the ion trajectories with MCBC*. The 3D electron distribution function and electric field of the background plasma are calculated self-consistently. The test beam ions are then tracked in it using MCBC which includes Coulomb, ionization and charge exchange collisions. The exact ion trajectories in the plasma and steady state 3D ion distribution at the extraction aperture are predicted and compared with previous simulations and experiments. D. H. Edgell et al., Rev. Sci. Instrum. 73, 641, 2002. ** J. S. Kim et al., Rev. Sci. Instrum. 79, 02B906, 2008.

TUP106	Effect of Surface Flow on Topography in Niobium Electropolishing	1038
	M.J. Kelley, C.E. Reece JLAB, Newport News, Virginia, USA L. Zhao The College of William and Mary, Williamsburg, USA
	Funding: This work has been supported by U.S. DOE Contract No. DE-AC05-06OR23177 to Jefferson Lab Electropolishing (EP) is reliably delivering improved performance of multi-celled niobium SRF accelerator cavities, attributed to the smoother surface obtained. This superior leveling is a consequence of an etchant concentration gradient layer that arises in the HF-H2SO4 electrolyte adjacent to the niobium surface during polishing. Electrolyte circulation raises the prospect that fluid flow adjacent to the surface might affect the diffusion layer and impair EP performance. In this study, preliminary bench-top experiments with a moving electrode apparatus were conducted. We find that flow conditions approximating cavity EP show no effects attributable to depletion layer disruption.

Paper

Title

Page

A Quasi-3D Model of Electron Cyclotron Resonance Ion Source (ECRIS)

1755

L. Zhao, B. Cluggish, J.S. Kim
Far-Tech, Inc., San Diego, California, USA

Funding: Grant supported by DOE office of Nuclear Physics
FAR-TECH, Inc is developing a hybrid, quasi-3D model to model charge breeding of an ion beam in an electron cyclotron resonance ion source. The model is a combination of 3D mapping of the plasma background calculated by GEM1D* and 3D tracking of the ion trajectories with MCBC**. The 3D electron distribution function and electric field of the background plasma are calculated self-consistently. The test beam ions are then tracked in it using MCBC which includes Coulomb, ionization and charge exchange collisions. The exact ion trajectories in the plasma and steady state 3D ion distribution at the extraction aperture are predicted and compared with previous simulations and experiments.
* D. H. Edgell et al., Rev. Sci. Instrum. 73, 641, 2002.
** J. S. Kim et al., Rev. Sci. Instrum. 79, 02B906, 2008.

TUP106

Effect of Surface Flow on Topography in Niobium Electropolishing

1038

M.J. Kelley, C.E. Reece
JLAB, Newport News, Virginia, USA
L. Zhao
The College of William and Mary, Williamsburg, USA

Funding: This work has been supported by U.S. DOE Contract No. DE-AC05-06OR23177 to Jefferson Lab
Electropolishing (EP) is reliably delivering improved performance of multi-celled niobium SRF accelerator cavities, attributed to the smoother surface obtained. This superior leveling is a consequence of an etchant concentration gradient layer that arises in the HF-H2SO4 electrolyte adjacent to the niobium surface during polishing. Electrolyte circulation raises the prospect that fluid flow adjacent to the surface might affect the diffusion layer and impair EP performance. In this study, preliminary bench-top experiments with a moving electrode apparatus were conducted. We find that flow conditions approximating cavity EP show no effects attributable to depletion layer disruption.