View source for Tuesday, July 26, 2:30pm ETD

== Agenda ==
Presentations:<br><br>
# [http://ace.phys.virginia.edu/MollerSpectrometer/199 photon simulations] (Michael Snider - high school summer student)
# [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 ==

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]]