Difference between revisions of "Ionization Effects - February 12, 2019"

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== For those calling in we'll use the Blue Jeans [https://cc.jlab.org/bluejeans] audio conference system. ==  
 
== For those calling in we'll use the Blue Jeans [https://cc.jlab.org/bluejeans] audio conference system. ==  
 
  Meeting ID: 366850636#  
 
  Meeting ID: 366850636#  
 +
Moderator Passcode: 2864
 
  Meeting URL (for video and/or audio call in): http://bluejeans.com/366850636
 
  Meeting URL (for video and/or audio call in): http://bluejeans.com/366850636
 
  Phone number (for audio call in): 1-888-240-2560
 
  Phone number (for audio call in): 1-888-240-2560
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: Requires useful long operating lifetime (e.g. 2mA is 1200C/week)
 
: Requires useful long operating lifetime (e.g. 2mA is 1200C/week)
 
: QE uniformity important for beam quality, especially parity violation experiments
 
: QE uniformity important for beam quality, especially parity violation experiments
−
: Applications include Electron Ion Collider, Polarized Positron Source or Moller Standard Model test
+
: Applications: Electron Ion Collider (>50 mA), Polarized Positron Source (>10mA) or Moller Standard Model test (>0.2 mA)
  
 
;Experimental Conditions (GaAs/GaAsP, tee shape electrode w/ grounded anode, rf pulsed IR laser)
 
;Experimental Conditions (GaAs/GaAsP, tee shape electrode w/ grounded anode, rf pulsed IR laser)
−
:Injector Test Facility (anode + vacuum)
+
:Injector Test Facility (anode + vacuum) => first 1 and 4 mA demos (in proceedings, unpublished)
−
:CEBAF (anode + vacuum + radiation + apertures + polarimetry)
+
:CEBAF (anode + vacuum + radiation + apertures + polarimetry) => CEBAF performance, laser scaling (in proceedings, unpublished)
  
 
;Results
 
;Results
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;Simulation Studies (IBSimu, GPT, Simion)
 
;Simulation Studies (IBSimu, GPT, Simion)
−
:Ion impact distribution at photocathode (#, energy, position) for CEBAF gun/geometry => show scaling depends upon optics
+
:Ion impact distribution at photocathode (#, energy, position) for CEBAF gun/geometry => demo how scaling depends upon optics
−
:Electron beam distribution and losses => validate radiation loss & vacuum load, useful to compare IBSimu w/ GPT model
+
:Electron beam distribution => demo how "too large" beam size leads to e-beam losses (validates radiation) to assess impact (gun vs. downstream)
−
:Ionization and secondaries distribution and total contribution to ions reaching cathode/anode gap
+
:GPT vs. IBSimu => not necessarily for paper, but for training and benchmarking?
  
 
; Outlook & Conclusions
 
; Outlook & Conclusions
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; 2018 Experiment to exploit increase of laser area to achieve >100C at >1mA from high polarization photocathodes
 
; 2018 Experiment to exploit increase of laser area to achieve >100C at >1mA from high polarization photocathodes
 
* Joe Grames, Phil Adderley, John Hansknecht, Reza Kazimi, Matt Poelker, Daniel Moser, Marcy Stutzman, R. Suleiman Shukui Zhang "Milliampere beam studies using high polarization photocathodes at the CEBAF Photoinjector" [[media:PSTP2017_Grames_v1.pptx]] [[media:PSTP2017_Grames_Final.pdf]]
 
* Joe Grames, Phil Adderley, John Hansknecht, Reza Kazimi, Matt Poelker, Daniel Moser, Marcy Stutzman, R. Suleiman Shukui Zhang "Milliampere beam studies using high polarization photocathodes at the CEBAF Photoinjector" [[media:PSTP2017_Grames_v1.pptx]] [[media:PSTP2017_Grames_Final.pdf]]
 +
 +
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[[Ionization Effects Meetings | Return to Ionization Effects Meetings]]

Latest revision as of 17:30, 6 December 2019

Meeting Info

We will meet Tuesday February 12 at 11:00 am EST in TL 2236.
Wiki: https://wiki.jlab.org/ciswiki/index.php/Ionization_Effects_-_February_12,_2019

For those calling in we'll use the Blue Jeans [1] audio conference system.

Meeting ID: 366850636# 
Moderator Passcode: 2864
Meeting URL (for video and/or audio call in): http://bluejeans.com/366850636
Phone number (for audio call in): 1-888-240-2560

Topics

Background Material
PRAB (lifetime studies w/ bulk GaAs) media:high current lifetime_in print.pdf
PSTP17 (lifetime study w/ GaAs/GaAsP) media:PSTP2017_Grames_v1.pptx media:PSTP2017_Grames_Final.pdf

Paper Outline

Motivation for high polarization at high current
Requires useful long operating lifetime (e.g. 2mA is 1200C/week)
QE uniformity important for beam quality, especially parity violation experiments
Applications: Electron Ion Collider (>50 mA), Polarized Positron Source (>10mA) or Moller Standard Model test (>0.2 mA)
Experimental Conditions (GaAs/GaAsP, tee shape electrode w/ grounded anode, rf pulsed IR laser)
Injector Test Facility (anode + vacuum) => first 1 and 4 mA demos (in proceedings, unpublished)
CEBAF (anode + vacuum + radiation + apertures + polarimetry) => CEBAF performance, laser scaling (in proceedings, unpublished)
Results
Injector Test Stand Results => 1mA and 4mA studies w/o polarimetry
CEBAF QWeak performance applying laser scaling, then operating 1-2 years @ 0.2mA w/ online Compton polarimetry vs. QE
CEBAF Scaling Experiment to achieve longest lifetime (>1000C) at >1 mA
CEBAF Polarization Experiment to measure polarization up to 1mA
Simulation Studies (IBSimu, GPT, Simion)
Ion impact distribution at photocathode (#, energy, position) for CEBAF gun/geometry => demo how scaling depends upon optics
Electron beam distribution => demo how "too large" beam size leads to e-beam losses (validates radiation) to assess impact (gun vs. downstream)
GPT vs. IBSimu => not necessarily for paper, but for training and benchmarking?
Outlook & Conclusions

Background Material

Ion impact degradation of GaAs photocathodes
2018 Experiment to exploit increase of laser area to achieve >100C at >1mA from high polarization photocathodes


Return to Ionization Effects Meetings

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