July 08, 2021 KLONG Design Meeting

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Meeting Time and Place

Thursday July 08, 2021, 1pm Bluejeans https://bluejeans.com/465620466

  • Present - Hovanes Egiyan, Moskov Amaryan, Stephanie Worthington, Keith Harding, Igor Strakovsky, Tim Whitlatch, Mark Stevens


  • Minutes from last meeting https://halldweb.jlab.org/wiki/index.php/June_24,_2021_KLONG_Design_Meeting
  • Media:KLONG_Be_target_overall.pdf
  • Existing PS vacuum chamber 5 cm high, entrance tube 3.5 cm round ID, magnet gap - 7 cm
  • Tungsten cooling
  • Preliminary 3D Model
    • Support/rollers
    • Tungsten cooling
    • 7 cm tube downstream to allow cooling tubes for tungsten
    • Be target holder
    • lead geometry
    • Borated Poly geometry
  • Heat absorbed by Be and Tungsten (.6kw and 6Kw respectively)
  • Requirements:
    • Cool tungsten plug to below temperature that affects lead (327°C)
    • 6 cm beam tube near final target
    • Moveable out of beamline
    • Be 98% pure or better

Minutes and Action Items

  • Went through 3D model changes with satisfactory acceptance
  • Showed cooling scheme for tungsten - ok to use copper plates on outer sides.
  • Cylinder of beryllium easily manufacturable, ok to use square tungsten
  • We discussed the beampipe downstream of the beryllium target. Currently there is a 3.5 cm opening in the pipe going into the Pair Spectrometer magnet. Since the beam spot size on the beryllium is about 4 cm (and enlarges to 6cm by the time it hits the liquid target), the PS vacuum chamber would need to be replaced with a 6cm opening beam pipe and be at least 6 cm downstream of this. The sweep magnet in collimator can stay as is and use 5 cm US of sweep.
  • Discussed heat absorption in beryllium and tungsten. Igor has a collaborator (Johan) to do some calculation in about 1 month. In the meantime assume linearly increasing absorption throughout.
  • ok to use 98% beryllium
  • Discussed cooling of the tungsten. Need to discuss with RadCon about using existing LCW system or a stand alone that keeps the water in the hall.
  • Encapsulation of beryllium to prevent dust? Aluminum foil ok? Epoxy encapsulation? Talk with ES&H
  • Discussed weight of lead. A cylinder of lead with OD of 100 cm and 16cm ID 130cm long (11.35 g/cc) weighs about 12.4 tons. With the current config of 2"x4"x8" lead bricks at 26 lbs each, we come up with about 2 tons more. It will cost about $60K for the bricks.
  • Need to put holes in the poly for steel bolts to attach. Ok to do was the verdict
  • There is concern as to whether the poly would compress over time. Need to look at properties and calculate. A couple of mm would be ok. We should get a piece to test.
  • Discussed Beam left horizontal motion of target assy to get out of the beamline. We may need to move a cable tray higher to accommodate.
  • Assume 5 year life of detector
  • Keith will check on wedge levelers to align the assembly
  • Moscov started discussion on the CPS. It was decided to wait until later in the process.
  • We should continue on the beamline installation in the collimator cave after beryllium target model is complete
  • Keith needs drawing numbers and naming conventions.

Action Items

  • Perform energy absorption calculation for beryllium and tungsten (Igor/Johan)
  • Get quotes on beryllium (Tim)
  • Proceed with tungsten cooling assuming linearly increasing energy absorption as well as calc for beryllium temperatures with only free convection. (Tim)
  • Work with RadCon to determine if existing LCW system can be used (Tim)
  • Work with ES&H to determine what is required to seal beryllium (Tim)
  • Follow up on calcs and test for borated poly compression. (Tim)
  • Keith to add wedge levelers to the design