Π polarizability Meeting Jan 28, 2021

Meeting Time And Location

01:00 pm EST (JLab time) Weekly Meeting

REMOTE during Covid-19

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Tentative Agenda

1. Previous CPP meeting: Jan 27, 2021
2. Announcements
3. CPP and NPP Readiness Review
4. Microscope move to 6 GeV (Richard)
5. CPP Configuration (Elton)
6. Discussion (All)

Minutes

Attending: Richard, Beni, Hovanes, Rory, Elton, Ilya, James McTyre

1. Previous CPP meeting: Jan 27, 2021
2. Announcements
3. CPP and NPP Readiness Review
4. Microscope move to 6 GeV (Richard)
   1. Review of concepts (Richard)
      • Nice overview of how the microscope is adjusted. The angle of electrons crossing the focal plane (beta) is about 12 degrees at the nominal 9 GeV coherent peak. At 6 GeV, beta ~ 9.5-8.5.
      • The change in angle is referred to as the "toe"
      • 17 fiber bundles in groups of 6 fibers need to be adjusted. One bundle, called a "popsicle stick", consists of 6 fibers, but groups of 3 are offset along the electron trajectory.
      • Three jig pieces need to be fabricated: a wedge to set the beta angle for the first fiber and two pieces that set the rails that hold the fibers
      • The change in beta from 12 deg -> 9 deg results in the length of the microscope along the focal plane increasing by about 30%.
   2. Mechanics (James McTyre)
      • Files have been recovered, but final iterations need to be verified
      • Design changes for the 6 GeV peak are needed
      • Promised to complete changes by April and write down detailed alignment procedure.
5. CPP Configuration (Elton)
6. Discussion (All)
   • Installing the hodoscope and microscope to cover the same region should be feasible
   • James: the fan cooling electronics might create pressure on the hodoscope pmts and might need adjustments.
   • Precise location of microscope.
   • Richard: For GlueX, the microscope is positioned to cover the coherent peak + 15% margin
   • Homework for CPP: Suggest margins and precise location of peak for the "6 GeV" position.
7. Next Meeting
   • Elton will reconvene the group in March to check progress.