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Title: Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

Abstract

Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from themore » quadrupole.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
925789
Report Number(s):
SLAC-PUB-13163
Journal ID: ISSN 1098-4402; TRN: US0803098
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.ST Accel.Beams 11:010101,2008; Journal Volume: 11
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CLOUDS; ELECTRONS; ENERGY SPECTRA; INSTABILITY; LANL; MAGNETS; PHYSICS; PROMPT ELECTRONS; PROTONS; QUADRUPOLES; SEEDS; STORAGE RINGS; TRAPPING; Accelerators,ACCPHY

Citation Formats

Macek, Robert J., Browman, Andrew A., Ledford, John E., /TechSource, Santa Fe /Los Alamos, Borden, Michael J., O'Hara, James F., McCrady, Rodney C., Rybarcyk, Lawrence J., Spickermann, Thomas, Zaugg, Thomas J., /Los Alamos, Pivi, Mauro T.F., and /SLAC. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring. United States: N. p., 2008. Web. doi:10.1103/PhysRevSTAB.11.010101.
Macek, Robert J., Browman, Andrew A., Ledford, John E., /TechSource, Santa Fe /Los Alamos, Borden, Michael J., O'Hara, James F., McCrady, Rodney C., Rybarcyk, Lawrence J., Spickermann, Thomas, Zaugg, Thomas J., /Los Alamos, Pivi, Mauro T.F., & /SLAC. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring. United States. doi:10.1103/PhysRevSTAB.11.010101.
Macek, Robert J., Browman, Andrew A., Ledford, John E., /TechSource, Santa Fe /Los Alamos, Borden, Michael J., O'Hara, James F., McCrady, Rodney C., Rybarcyk, Lawrence J., Spickermann, Thomas, Zaugg, Thomas J., /Los Alamos, Pivi, Mauro T.F., and /SLAC. Mon . "Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring". United States. doi:10.1103/PhysRevSTAB.11.010101. https://www.osti.gov/servlets/purl/925789.
@article{osti_925789,
title = {Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring},
author = {Macek, Robert J. and Browman, Andrew A. and Ledford, John E. and /TechSource, Santa Fe /Los Alamos and Borden, Michael J. and O'Hara, James F. and McCrady, Rodney C. and Rybarcyk, Lawrence J. and Spickermann, Thomas and Zaugg, Thomas J. and /Los Alamos and Pivi, Mauro T.F. and /SLAC},
abstractNote = {Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the quadrupole.},
doi = {10.1103/PhysRevSTAB.11.010101},
journal = {Phys.Rev.ST Accel.Beams 11:010101,2008},
number = ,
volume = 11,
place = {United States},
year = {Mon Mar 17 00:00:00 EDT 2008},
month = {Mon Mar 17 00:00:00 EDT 2008}
}