Difference between revisions of "Tuesday, July 26, 2:30pm ETD"

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(New page: == Agenda == Presentations:<br><br> # [http://ace.phys.virginia.edu/MollerSpectrometer/199 photon simulations] (Michael Snider - high school summer student) # acceptance plots from collima...)
 
(→‎Minutes)
 
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Presentations:<br><br>
 
Presentations:<br><br>
 
# [http://ace.phys.virginia.edu/MollerSpectrometer/199 photon simulations] (Michael Snider - high school summer student)
 
# [http://ace.phys.virginia.edu/MollerSpectrometer/199 photon simulations] (Michael Snider - high school summer student)
−
# acceptance plots from collimator optimization study (Sereres)
+
# [http://ace.phys.virginia.edu/MollerSpectrometer/200 acceptance plots from collimator optimization study] (Sereres)
−
 
+
# Discussion - [https://hallaweb.jlab.org/wiki/index.php/MOLLER_Simulations Other projects]
  
 
== Minutes ==
 
== Minutes ==
  
 +
Action items in '''bold'''.
 +
 +
Attendance: Mark Pitt, Michael Snider, Michael Gericke, Anna Lee, Damon Spayde, Seamus Riordan, Sereres Johnston, Wouter Deconinck (minutes), Juliette Mammei (chair)
 +
 +
* Michael Snider presented results from his photon background studies (see elog entry 199, link in agenda)
 +
** attachment 2: previous results could be replicated for ee, ep, ine, and photon background
 +
** table 1: new results
 +
*** photon background from ep is largest
 +
*** total photon background rate is 13.7 GHz, compared to 171.7 GHz moller rate
 +
** attachment 1: origin of the photon background is around the collimator edges, similar for all processes
 +
** attachment 3: simulation with helium, very similar but recent results and not sure if correct
 +
*** thickness of helium only 0.5% (according to Juliette)
 +
*** origin for He study: Roger's suggestion to keep the petal beamline, but fill it with He, primary beam would go through He
 +
*** Mark: why do you expect any difference if most of the photons are shown to come from the collimator edges?
 +
**** Juliette: from the table it seems that 2 GHz of ee photons come from other sources than target and collimator
 +
*** Wouter: primary beam through He not simulated, but Juliette points out small UHV beamline inside He
 +
** acceptance defining collimator is visible -> not good
 +
** no photons from target visible (z pos < 4m) -> good
 +
** '''Sereres''' will take this over from Michael
 +
 +
* Sereres presented results from her collimator optimization studies (see elog 200, link in agenda)
 +
** progress in developing figure of merit and separation according to polar angles
 +
** attachment 1: radius versus theta_CM -> "eyebrow" (compare to Qweak "moustache")
 +
*** KK rule of thumb: lower right panel should be as vertical as possible by tweaking field map (points to good focusing)
 +
*** reasons for KK's rule of thumb not well understood by those present
 +
*** presented figures use default conductor field map
 +
*** '''Sereres''' will make these plots for the proposal field map
 +
*** '''Sereres''' will turn off radiation in G4 and compare with results from Tosca
 +
** attachment 5: top right is how KK wants this to look
 +
*** need to trim using collimators, but without changing the magnet and without affecting FOM
 +
** '''Sereres''' will repeat these studies for different fieldmaps and collimator geometries (looking for input...)
 +
** attachment 16-17: lower right should be symmetric (as in attachment 15)
 +
** attachment 20: radial width primarily determined by midrange scattering angles, shrinking this width will reduce photon backgrounds
 +
** '''Sereres''' will look at different detector plan positions, less than 26 m, but 2 m range, e.g. steps of 50 cm
 +
 +
* Other projects listed on Moller simulations page
 +
** '''Michael Gericke''' will update webpage with plan of attack for detector simulations
 +
** GDML support on central G4 installation is missing
  
 +
* Meeting time: every two weeks, same time, until fall semester starts, then revisit
 +
* '''Seamus''' will move SVN repository from Umass to JLab ('''someone''' should tell him)
  
  
 
<br><br> Return to [[MOLLER at 11 GeV E09-005]]
 
<br><br> Return to [[MOLLER at 11 GeV E09-005]]

Latest revision as of 09:46, 27 July 2011

Agenda

Presentations:

  1. photon simulations (Michael Snider - high school summer student)
  2. acceptance plots from collimator optimization study (Sereres)
  3. Discussion - Other projects

Minutes

Action items in bold.

Attendance: Mark Pitt, Michael Snider, Michael Gericke, Anna Lee, Damon Spayde, Seamus Riordan, Sereres Johnston, Wouter Deconinck (minutes), Juliette Mammei (chair)

  • Michael Snider presented results from his photon background studies (see elog entry 199, link in agenda)
    • attachment 2: previous results could be replicated for ee, ep, ine, and photon background
    • table 1: new results
      • photon background from ep is largest
      • total photon background rate is 13.7 GHz, compared to 171.7 GHz moller rate
    • attachment 1: origin of the photon background is around the collimator edges, similar for all processes
    • attachment 3: simulation with helium, very similar but recent results and not sure if correct
      • thickness of helium only 0.5% (according to Juliette)
      • origin for He study: Roger's suggestion to keep the petal beamline, but fill it with He, primary beam would go through He
      • Mark: why do you expect any difference if most of the photons are shown to come from the collimator edges?
        • Juliette: from the table it seems that 2 GHz of ee photons come from other sources than target and collimator
      • Wouter: primary beam through He not simulated, but Juliette points out small UHV beamline inside He
    • acceptance defining collimator is visible -> not good
    • no photons from target visible (z pos < 4m) -> good
    • Sereres will take this over from Michael
  • Sereres presented results from her collimator optimization studies (see elog 200, link in agenda)
    • progress in developing figure of merit and separation according to polar angles
    • attachment 1: radius versus theta_CM -> "eyebrow" (compare to Qweak "moustache")
      • KK rule of thumb: lower right panel should be as vertical as possible by tweaking field map (points to good focusing)
      • reasons for KK's rule of thumb not well understood by those present
      • presented figures use default conductor field map
      • Sereres will make these plots for the proposal field map
      • Sereres will turn off radiation in G4 and compare with results from Tosca
    • attachment 5: top right is how KK wants this to look
      • need to trim using collimators, but without changing the magnet and without affecting FOM
    • Sereres will repeat these studies for different fieldmaps and collimator geometries (looking for input...)
    • attachment 16-17: lower right should be symmetric (as in attachment 15)
    • attachment 20: radial width primarily determined by midrange scattering angles, shrinking this width will reduce photon backgrounds
    • Sereres will look at different detector plan positions, less than 26 m, but 2 m range, e.g. steps of 50 cm
  • Other projects listed on Moller simulations page
    • Michael Gericke will update webpage with plan of attack for detector simulations
    • GDML support on central G4 installation is missing
  • Meeting time: every two weeks, same time, until fall semester starts, then revisit
  • Seamus will move SVN repository from Umass to JLab (someone should tell him)




Return to MOLLER at 11 GeV E09-005

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