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Title: Electron Recombination in a Dense Hydrogen Plasma

Abstract

A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced plasma inside the cavity. Varying beam intensities, gas pressures and electric fields were tested. Beam induced ionized electrons load the cavity, thereby decreasing the accelerating gradient. The extent and duration of this degradation has been measured. A model of the recombination between ionized electrons and ions is presented, with the intent of producing a baseline for the physics inside such a cavity used in a muon accelerator. Analysis of the data taken during the summer of 2011 shows that self recombination takes place in pure hydrogen gas. The decay of the number of electrons in the cavity once the beam is turned off indicates self recombination rather than attachment to electronegative dopants or impurities. The cross section of electron recombination grows for larger clusters of hydrogen and so at the equilibrium of electron production and recombination in the cavity, processes involving H{sub 5}{sup +} or larger clusters must be taking place. The measured recombination rates during this time match or exceed the analytic predicted values. The accelerating gradient in the cavity recovers fully in time for themore » next beam pulse of a muon collider. Exactly what the recombination rate is and how much the gradient degrades during the 60 ns muon collider beam pulse will be extrapolated from data taken during the spring of 2012.« less

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1048437
Report Number(s):
FERMILAB-CONF-12-434-APC
TRN: US1204206
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Conference
Journal Name:
Conf.Proc.C1205201:217-219,2012
Additional Journal Information:
Conference: Presented at the 3rd International Particle Accelerator Conference (IPAC-2012), New Orleans, Louisiana, 20-25 May 2012
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; CROSS SECTIONS; DECAY; ELECTRIC FIELDS; ELECTRONS; HYDROGEN; IMPURITIES; MUONS; PHYSICS; PLASMA; PRODUCTION; PROTON BEAMS; RECOMBINATION; Accelerators

Citation Formats

Jana, M R, Johnstone, C, Kobilarcik, T, Koizumi, G M, Moretti, A, Popovic, M, Tollestrup, A V, Yonehara, K, /Fermilab, Leonova, M A, Schwarz, T A, /Fermilab, Chung, M, and /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic. Electron Recombination in a Dense Hydrogen Plasma. United States: N. p., 2012. Web.
Jana, M R, Johnstone, C, Kobilarcik, T, Koizumi, G M, Moretti, A, Popovic, M, Tollestrup, A V, Yonehara, K, /Fermilab, Leonova, M A, Schwarz, T A, /Fermilab, Chung, M, & /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic. Electron Recombination in a Dense Hydrogen Plasma. United States.
Jana, M R, Johnstone, C, Kobilarcik, T, Koizumi, G M, Moretti, A, Popovic, M, Tollestrup, A V, Yonehara, K, /Fermilab, Leonova, M A, Schwarz, T A, /Fermilab, Chung, M, and /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic. Tue . "Electron Recombination in a Dense Hydrogen Plasma". United States. https://www.osti.gov/servlets/purl/1048437.
@article{osti_1048437,
title = {Electron Recombination in a Dense Hydrogen Plasma},
author = {Jana, M R and Johnstone, C and Kobilarcik, T and Koizumi, G M and Moretti, A and Popovic, M and Tollestrup, A V and Yonehara, K and /Fermilab and Leonova, M A and Schwarz, T A and /Fermilab and Chung, M and /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic},
abstractNote = {A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced plasma inside the cavity. Varying beam intensities, gas pressures and electric fields were tested. Beam induced ionized electrons load the cavity, thereby decreasing the accelerating gradient. The extent and duration of this degradation has been measured. A model of the recombination between ionized electrons and ions is presented, with the intent of producing a baseline for the physics inside such a cavity used in a muon accelerator. Analysis of the data taken during the summer of 2011 shows that self recombination takes place in pure hydrogen gas. The decay of the number of electrons in the cavity once the beam is turned off indicates self recombination rather than attachment to electronegative dopants or impurities. The cross section of electron recombination grows for larger clusters of hydrogen and so at the equilibrium of electron production and recombination in the cavity, processes involving H{sub 5}{sup +} or larger clusters must be taking place. The measured recombination rates during this time match or exceed the analytic predicted values. The accelerating gradient in the cavity recovers fully in time for the next beam pulse of a muon collider. Exactly what the recombination rate is and how much the gradient degrades during the 60 ns muon collider beam pulse will be extrapolated from data taken during the spring of 2012.},
doi = {},
journal = {Conf.Proc.C1205201:217-219,2012},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {5}
}

Conference:
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