MOLLER Pion Background Meeting Wednesday, November 16, 2016 3:00pm EST

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Previous Meeting: MOLLER_Pion_Background_Meeting_Wednesday,_November_2,_2016_3:00pm_EST

Meeting Information

BlueJeans Call Information


Phone Number: 1-888-240-2560

Meeting ID: 624029893


  • Wouter: Detector concept in simulation
    • Remoll-geometry-tree-eabd7b7d954b57db5c0c6bfb39bba02bb8a60c79.png
    • Remoll-side-view-f8a758f74b47dbeb35643f7486faf1d599b51c06.png Remoll-back-view-f8a758f74b47dbeb35643f7486faf1d599b51c06.png
    • Remoll-side-view-cerenkov-f8a758f74b47dbeb35643f7486faf1d599b51c06.png Remoll-back-view-cerenkov-f8a758f74b47dbeb35643f7486faf1d599b51c06.png
    • Warning:

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomNav0003
     issued by : G4Navigator::GetGlobalExitNormal()
WARNING> Expected normal-global-frame to be valid,  i.e. a unit vector!
 - but |normal|   = 0  - and |normal|^2 = 0
which differs from 1.0 by -1
  n = (0,0,0)
Global point: (-549.2642695,-978.7146481,31450)
Volume: pionDetectorGEMOpenSector_logical_PV
Solid: pionDetectorGEMOpenSector_solid, Type: G4Tubs

  • Scott: Implementation of lead wall and strawman pion detector.
    • Separate pion development branch
    • Initial detector prototype.
  • Jacob: Starting to work on pion simulations.
  • David: present detector concept.
  • Any new business?


Attendees: Kurtis, Wouter, Seamus, David, Mark Pitt, Jacob, Scott

Not Attending: KK(traveling)

Scribe: Kurtis

  • Wouter- Detector concept in simulation
    • David: Any concern with detector concept. KK did discuss the possibility of some type of counting mode asymmetry measurement, which would lead to better particle ID.
    • David: Biggest concern from the collaboration meeting is that we wont be able to definitely know the pion rate and energy spectrum before and after the wall.
    • David: No need to really looking into some special asymmetry measurement for the directors review.
    • Wouter: Implemented the objects from the cad drawing into gdml using primitives. Looking at the images taken from gdml.
    • The geometry tree shows the volumes that Wouter has implemented. Note that this currently doesn't show the really main detectors volumes.
    • The GEMS should be places in one open sector and 180 degrees into the opposite closed sector. This would simplify the support structure you would need for these detectors.
    • Wouter: Looking at a complete detector package about 2 meters long. Still flexible, can be compressed depending on requirements.
    • David: Should confirm with KK the actual available space for the detector system.
    • Wouter: Optical photons are being generated via the Cerenkov process. Still not being collected by the pseudo PMT photo-cathode. Work in progress.
    • Wouter: Red electrons, green neutrals. Incident electrons with lead wall set to vacuum. Simply for testing purposes.
    • Wouter: Still working on optical surfaces, no overlap in the geometry or memory leaks. Still a problem with the geometry around the GEMs and trigger scintillator. Seamus: Could be a problem with parallel faces.
    • Wouter: Had to disable Scott's geometry to implement this geometry.
    • Wouter: This is all implemented in GDML. Could implement reflective material in between the lucite sheets. Can change from a 5 layers to single layers.
    • David: Scott should move to this new geometry? Wouter: No, because it is more difficult to look at the energy distributions. A good middle ground would be to implement a simple sensitive volume into the more complete geometry. Wouter will add it.
    • Once the optical properties are a bit more farther along Jacob can start working on optimizing the lucite detectors.
  • David: Major physics questions for directors review
    • Thickness of lead? Looking for 45 X_0 (including Shower max),
    • Energy spectrum of the electrons and pions before and after the lead wall.
    • Back of envelop calculation of the total absorbed dose for the lucite over the life time of the experiment.
    • Dilution in the open and closed sectors.
    • Particle multiplicity, really need more detectors than just GEMS. Really worry about particle track identification.
    • Possible scintillator fiber detector might help instead of GEMS.
  • Calorimeter, would help with background identification. Need to identify the specs regarding this detector system.