July 08, 2021 KLONG Design Meeting
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
- Existing PS vacuum chamber 5 cm high, entrance tube 3.5 cm round ID, magnet gap - 7 cm
- Tungsten cooling
- Preliminary 3D Model
- 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)
- 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.
- 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