Difference between revisions of "Laser Size Paper - Nov 8, 2019"

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(Created page with "== Meeting Info == We will meet Friday Nov 8 in TL-2221.. == For those calling in we'll use the Blue Jeans [https://cc.jlab.org/bluejeans] audio conference system. == Meet...")
 
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== Meeting Info ==
 
== Meeting Info ==
  We will meet Friday Nov 8 in TL-2221..
+
  We will meet Friday Nov 8 in TL-2221.
  
 
== 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: 838158220#  
 
  Moderator Passcode: 2864
 
  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/838158220
 
  Phone number (for audio call in): 1-888-240-2560
 
  Phone number (for audio call in): 1-888-240-2560
  
== Topics ==
+
;What are the question we'd like to answer in the paper ?
 +
[[media:191108_ion_paper.pptx]]
 +
 
 
;Background Material
 
;Background Material
 
:PRAB (lifetime studies w/ bulk GaAs) [[media:high current lifetime_in print.pdf]]
 
: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]]
 
: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 first 1 and 4 mA demos (in proceedings, unpublished)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 CEBAF performance, laser scaling (in proceedings, unpublished)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
 
* J. Grames, R. Suleiman, P. A. Adderley, J. Clark, J. Hansknecht, D. Machie, M. Poelker, and M. L. Stutzman, "''Charge and fluence lifetime measurements of a DC high voltage GaAs photogun at high average current''", [http://journals.aps.org/prstab/pdf/10.1103/PhysRevSTAB.14.043501 Phys. Rev. ST Accel. Beams '''14''', 043501 (2011)], [[media:high current lifetime_in print.pdf]]
 
 
; 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]]
 

Revision as of 12:55, 8 November 2019

Meeting Info

We will meet Friday Nov 8 in TL-2221.

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

Meeting ID: 838158220# 
Moderator Passcode: 2864
Meeting URL (for video and/or audio call in): http://bluejeans.com/838158220
Phone number (for audio call in): 1-888-240-2560
What are the question we'd like to answer in the paper ?

media:191108_ion_paper.pptx

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