Difference between revisions of "Π polarizability Meeting Apr 12, 2021"

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# Announcements
 
# Announcements
 
# [[CPP and NPP Readiness Review]]
 
# [[CPP and NPP Readiness Review]]
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4883 Microscope move to 6 GeV] (Richard)
+
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4972 Update on CPP Configuration] (Elton)
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4882 CPP Configuration] (Elton)
+
# Updates on design (Richard/Jim)
 
# Discussion (All)
 
# Discussion (All)
  
 
== Minutes ==
 
== Minutes ==
'' Attending: Richard, Beni, Hovanes, Rory, Elton, Ilya, James McTyre
+
'' Attending: Richard, Beni, Hovanes, Rory, Elton, Ilya, James McTyre, Mark
  
 
# Previous CPP meeting: [[π polarizability Meeting Jan 28, 2021|Jan 28, 2021]]
 
# Previous CPP meeting: [[π polarizability Meeting Jan 28, 2021|Jan 28, 2021]]
 +
#* We reviewed the minutes from the last meeting as a reminder of issues raised
 
# Announcements
 
# Announcements
 
# [[CPP and NPP Readiness Review]]
 
# [[CPP and NPP Readiness Review]]
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4883 Microscope move to 6 GeV] (Richard)
+
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4972 Update on CPP Configuration] (Elton)
## Review of concepts (Richard)
+
#* The slides were presented comments/questions were made
##* 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.
+
#* Richard: Noted that not all hodoscope counters have the protective cylindrical cover. We need to keep this in mind and likely add protection before moving the microscope.
##* The change in angle is referred to as the "toe"
+
#* Richard: Are the cables sufficiently long? Tim: racks are on wheels with flexible AC power so they can be moved. Hovanes: The goniometer controls are in one of the racks, so moving the rack might affect cables for this system. -> We need to revisit cabling in more detail.
##* 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.  
+
#* [Note added 4/13/2021 from Tim] "I went into the tagger with Cris Stanislav today and we determined the racks/cabling can accommodate the move."
##* 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
+
#* Concrete blocks: They are not part of the RadCon configuration so they can be moved downstream to continue to shadow the microscope from the dump.
##* The change in beta from 12 deg -> 9 deg results in the length of the microscope along the focal plane increasing by about 30%.
+
#* Beni: Inquired about acceptance change in TPOL when peak is moved down to 6 GeV. Richard: No effect in TPOL, but acceptance of the PS needs to be watched.
## Mechanics (James McTyre)
+
#* Agreed that the microscope top range should be set to 6.2 GeV, 0.2 GeV above the nominal coherent edge. Elton provided parameters for this configuration that should be checked by James.
##* Files have been recovered, but final iterations need to be verified
+
# Updates on design (James)
##* Design changes for the 6 GeV peak are needed
+
#* The documentation is collected in the [https://zeus.phys.uconn.edu/wiki/index.php/Student_Projects_in_Nuclear_Physics wiki at UConn].
##* Promised to complete changes by April and write down detailed alignment procedure.
+
#* Description of the microscope move can be found at [https://zeus.phys.uconn.edu/wiki/index.php/Moving_the_Tagger_Microscope Moving the Tagger Microscope]
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4882 CPP Configuration] (Elton)
+
#* The calculation for new positions can be found at [https://zeus.phys.uconn.edu/wiki/index.php/Calculating_the_move Calculating the Tagger Microscope Move]
 +
#* Some of the links to calculations are still pointing to (private) areas on James' computer, but will be moved in coordination with Richard to a more standard location.
 +
#* One important point is that rails cannot accommodate all 17 bundles. Only bundles 1-16 willl fit. This results in having 96 microscope columns instead of 100. However, this will provide sufficient coverage for CPP.
 +
#* James' calculations for the microscope were referenced to yc=0, whereas the coordinate designation indicates they should be at yc=-0.9 cm, which Elton used in his calculations
 +
#* James will update the calculations and generate locations for the microscope with a maximum energy of 6.2 GeV. These will be compared to Elton's numbers. Once any discrepancies are resolved, the drawings can be updated and the 3 new alignment pieces will be ordered in preparation for the move.
 
# Discussion (All)
 
# 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.
 
# Next Meeting
 
#* Elton will reconvene the group in March to check progress.
 

Latest revision as of 13:37, 13 April 2021

Meeting Time And Location

01:30 pm EST (JLab time) Weekly Meeting

REMOTE during Covid-19

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Action Items

Tentative Agenda

  1. Previous CPP meeting: Jan 28, 2021
  2. Announcements
  3. CPP and NPP Readiness Review
  4. Update on CPP Configuration (Elton)
  5. Updates on design (Richard/Jim)
  6. Discussion (All)

Minutes

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

  1. Previous CPP meeting: Jan 28, 2021
    • We reviewed the minutes from the last meeting as a reminder of issues raised
  2. Announcements
  3. CPP and NPP Readiness Review
  4. Update on CPP Configuration (Elton)
    • The slides were presented comments/questions were made
    • Richard: Noted that not all hodoscope counters have the protective cylindrical cover. We need to keep this in mind and likely add protection before moving the microscope.
    • Richard: Are the cables sufficiently long? Tim: racks are on wheels with flexible AC power so they can be moved. Hovanes: The goniometer controls are in one of the racks, so moving the rack might affect cables for this system. -> We need to revisit cabling in more detail.
    • [Note added 4/13/2021 from Tim] "I went into the tagger with Cris Stanislav today and we determined the racks/cabling can accommodate the move."
    • Concrete blocks: They are not part of the RadCon configuration so they can be moved downstream to continue to shadow the microscope from the dump.
    • Beni: Inquired about acceptance change in TPOL when peak is moved down to 6 GeV. Richard: No effect in TPOL, but acceptance of the PS needs to be watched.
    • Agreed that the microscope top range should be set to 6.2 GeV, 0.2 GeV above the nominal coherent edge. Elton provided parameters for this configuration that should be checked by James.
  5. Updates on design (James)
    • The documentation is collected in the wiki at UConn.
    • Description of the microscope move can be found at Moving the Tagger Microscope
    • The calculation for new positions can be found at Calculating the Tagger Microscope Move
    • Some of the links to calculations are still pointing to (private) areas on James' computer, but will be moved in coordination with Richard to a more standard location.
    • One important point is that rails cannot accommodate all 17 bundles. Only bundles 1-16 willl fit. This results in having 96 microscope columns instead of 100. However, this will provide sufficient coverage for CPP.
    • James' calculations for the microscope were referenced to yc=0, whereas the coordinate designation indicates they should be at yc=-0.9 cm, which Elton used in his calculations
    • James will update the calculations and generate locations for the microscope with a maximum energy of 6.2 GeV. These will be compared to Elton's numbers. Once any discrepancies are resolved, the drawings can be updated and the 3 new alignment pieces will be ordered in preparation for the move.
  6. Discussion (All)