Mar 5, 2009 Calorimetry

Teleconference Time: 11:00 EST/10:00 CST

• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 39527048# (remember the "#")

Items for followup from Feb 19 meeting

1. Resolution studies (Blake)
   • Develop criteria for evaluating resolution studies
   • Study impact of inactive material at the end of BCAL on acceptance.
   • Check what configuration (thresholds, step sizes, stack? parameters for secondaries, etc) is being used for the Hall D simulations (Regina)
2. Review options for import/export to Chile (loans, donations, transfers, etc.)

Documents to Review

1. Fibers
   • Kuraray measurements of light output
   • Kuraray measurements of attenuation length
2. APDs
   • An improved Shashlyk calorimeter
   • Development of Shashlyk calorimeter for KOPIO

Tentative Agenda

1. Announcements
2. FCAL Update
   1. MOU
   2. rad-hard glass insert
   3. magnetic shield tests (Field Sensitivity Plots)
3. Simulations
4. BCAL Update
   1. Preparations for construction
   2. Fiber measurements (Beni) GlueX Doc 1225
   3. Acceptance date for fibers (fiber arrival at JLab on Feb 13).
5. BCAL Readout
   1. SiPM and cooling GlueX-doc-1214(Elton)
   2. FM pmts (USM?)
   3. APD option (Eugene)
6. Review of Action Items

Minutes

Attendees: Elton, Tim, Beni, Eugene, Fernando (JLab), Ashot (), Matt, Claire, Ryan, Mijahlo (Indiana), Alam, Joaquin, Manuel, and Will (USM), Andrei (Regina)

1. Announcements
2. FCAL Update
   1. MOU revised and sent to JLab for comments.
   2. Rad-hard glass insert: Brad is studying clusters at boundaries between rad hard and regular lead glass.
   3. magnetic shield tests (Field Sensitivity Plots)
      • Data were shown that indicate that shielding must be included to reduce internal fields to 1 G level.
      • Using iron rods to "focus" field near pmt for specific tests.
      • Measurements of E852 mu-metal shields show magnetization on the few Gauss level in couple cm spots. They have been magnetized along the way. Annealing is possible with thermal treatment up to about 900 deg C in vacuum or hydrogen atmosphere to avoid oxydation.
      • Found that the educational discounted ANSYS price is $3800/year. John could learn and use ANSYS to support Hall D efforts, such as calculating magnetic fields. Tim will evaluate the benefit of offloading work on JLab staff.
3. Simulations
   • Blake was not available and no simulation meeting this week.
   • Matt will check the implementation of readout parameters (PDE, DR, etc) and how these effect low energy performance.
   • It is important to understand the limitations of reconstructing showers near threshold as input to evaluating various readout options. For example, APDs have very little intrinsic gain and therefore noise is a critical concern.
4. BCAL Update
   1. Preparations for construction
   2. Fiber measurements: Kuraray has sent us the data from the measurements of their first article samples. They all satisfy our atten length specification of > 300 cm. The light output measurement is only relative.
      • (Beni) GlueX Doc 1225. Beni presented a first look at the 'jlab' fibers, which indicate that they satisfy our specifications for attenuation length and light output. Further tests are necessary to understand some systematics in the measurements.
      • Acceptance date for fibers (fiber arrival at JLab on Feb 13).
      • The shipment of fibers to Regina was just released on Tuesday. See e-mail. Regina is ready to test them.
5. BCAL Readout
   1. SiPM and cooling GlueX-doc-1214(Elton)
   2. FM pmts (USM?) USM connection dropped out before this item on the agenda.
   3. APD option:
      • Eugene has circulated references to the KOPIO Shashlyk calorimeter that has used APDs very successfully. Investigation of applicability of this sensor to our application are ongoing, especially considerations of noise levels, as the gain is rather small.
      • Eugene asked Andrei if they could collect the distribution of photons expected for numbers of photons for various showers (especially at low energies, e.g. 50 MeV - 200 MeV). Some of these studies have already been reported and can be pulled out from previous notes. Additional shower may have to be generated using the stand-alone MC.
      • The operation of APDs must be stabilized (~18 deg C).
      • Need to investigate electronics (amplifier and power supply) contributions to noise.
      • Run at relatively high bias (~2000 V) for high gain operation.
6. Review of Action Items