11/10/2020

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Present: T. Averett, E. Chudakov, M.Dalton, A.Deur, C. Keith, D. Keller, S.Širca, J.Steven,

  • We need to decide wether we want the target to operate in frozen-spin mode, or in continuously polarizing mode.
    • Frozen-spin mode allows for transverse polarization, but has a lower limit in term of maximum photon flux.
    • Continuously polarizing mode allows for larger flux, but transverse polarization is very difficult.
  • AD prefers the frozen-spin option in order to accommodate other experiments than GDH. If flux becomes an issue, two options are possible: 1) a beam hardener, 2) modify the beam line (primary collimator, active collimator, secondary collimator) to allow for larger beam size.
  • Eugene and Chris emphasized that to increase the odd of funding from JLab's management, expanding the physics program is important. Looking for external funding will also help and can be started now.
  • Dustin will chose a topic from is LOI to develop into a proposal and make a presentation next month.
  • We discuss how to go forward on a joined UVa-W&M grant. Chris Keith listed possibilities of equipement/cost that could be covered by an external funding:
    • Microwave system:
      • cost: ? (relatively cheap)
      • justification: advance in RF technology (what does this bring in practice compared to re-using the Hall B RF system?)
    • Machining of part of the dilution fridge:
      • Cost ?
      • Justification:
        • Less costly than JLab in-house machining (?).
        • This type of contribution was already provided by UVa for other targets.
      • Caveats: constraint from JLab safety regulation.
    • Cryo-free polarizing magnet:
      • cost $250k
      • justification: A system is already available from Hall B but it uses cooling He4. At the moment, it seems doubtful that the Hall D fridge can comfortably provide enough cooling for the solenoid+FROST. Reducing the cooling power of the target by having a cryo-free magnet might enable us to use the Hall D fridge and thus avoid the significant cost of bringing cooling lines from CHL or ESR.
    • Pumps:
      • cost ?
      • Justification: most pumps are available from the Hall B system. One or two may need to be replaced.
    • Manpower:
      • cost ?
      • Justification: Manpower is very limited at JLab. Outside manpower will be helpful, especially a designer.