PAC09 - List of Authors (Browman, A. A.)

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Browman, A. A.

Paper	Title	Page
FR5RFP079	Recent Observations, Experiments and Simulations of Electron Cloud Buildup in Drift Spaces and Quadrupole Magnets at the Los Alamos PSR	4722
	R.J. Macek, R.C. McCrady, L. Rybarcyk, T. Zaugg LANL, Los Alamos, New Mexico A. A. Browman TechSource, Santa Fe, New Mexico
	Funding: Work supported, in part, by DOE SBIR Grant No. DE-FG02-04ER84105 and CRADA No. LA05C10535 between TechSource, Inc. and the Los Alamos National Laboratory. Recent beam studies have focused on understanding the main sources and locations of electron clouds (EC) which drive the observed e-p instability at the Los Alamos Proton Storage Ring (PSR). Strong EC signals are observed in drift spaces and quadrupole magnets at PSR which together cover ~65% of the ring circumference. New results making use of two longitudinal barriers to isolate the drift space electron diagnostic provide definitive evidence that most of the drift space EC signal is “seeded” by electrons ejected longitudinally by ExB drifts from adjacent quadrupole magnets. This result can explain why weak solenoids and TiN coatings in several drifts spaces had no effect on the e-p instability threshold. Modeling of EC generation in 3D quadrupoles using a modified version of the POSINST code shows that a sizeable fraction of the electrons generated in the quadrupoles are ejected longitudinally into the adjacent drifts. The experimental findings and simulation results will be presented.

Paper

Title

Page

Recent Observations, Experiments and Simulations of Electron Cloud Buildup in Drift Spaces and Quadrupole Magnets at the Los Alamos PSR

4722

R.J. Macek, R.C. McCrady, L. Rybarcyk, T. Zaugg
LANL, Los Alamos, New Mexico
A. A. Browman
TechSource, Santa Fe, New Mexico

Funding: Work supported, in part, by DOE SBIR Grant No. DE-FG02-04ER84105 and CRADA No. LA05C10535 between TechSource, Inc. and the Los Alamos National Laboratory.

Recent beam studies have focused on understanding the main sources and locations of electron clouds (EC) which drive the observed e-p instability at the Los Alamos Proton Storage Ring (PSR). Strong EC signals are observed in drift spaces and quadrupole magnets at PSR which together cover ~65% of the ring circumference. New results making use of two longitudinal barriers to isolate the drift space electron diagnostic provide definitive evidence that most of the drift space EC signal is “seeded” by electrons ejected longitudinally by ExB drifts from adjacent quadrupole magnets. This result can explain why weak solenoids and TiN coatings in several drifts spaces had no effect on the e-p instability threshold. Modeling of EC generation in 3D quadrupoles using a modified version of the POSINST code shows that a sizeable fraction of the electrons generated in the quadrupoles are ejected longitudinally into the adjacent drifts. The experimental findings and simulation results will be presented.