General Meeting Summary 12/19/19

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NPS COLLABORATION MEETING (3 February 2020)

  • TCS discussion
  • Helpful to show in presentation the status of rates/detector simulations, e.g. to demonstrate that one can record the data at the expected rates. This includes realistic background simulation with magnetic fields etc.
  • To do list
  • Orsay engineers will be available on 4 February for further discussions


MAGNET (Bogdan)

  • ODU team has been taking data - analysis ongoing


FRAME - MAGNETIC SHIELDING (Carlos)

  • Background: magnetic field at NPS PMTs higher than desired with original shielding model (PMTs with mu metal). At 0.6T calculated field up to 200 G at location of PMTs. Additional shielding not easy, in particular at 3m position.
  • New shielding design: uses mu metal mesh - simulations show that with this shielding magnetic fields go down to an acceptable level - demonstrates that order 100-200 G fields can be mitigated. The new design has been implemented (major change) in the frame design.
  • this shielding works because have many plates that can pick up the field
  • 4-cm spacing based on calculations: size of box ~1m, iron gap and mu metal have to be normalized to size of box
  • with the new shielding design likely less iron in front of calorimeter too
  • Action item: real simulations at full field


MAGNETIC FIELD SIMULATIONS (Ho San)

  • With new configuration 0.2 Tm sufficient to sweep away charged particle background
  • Background dose calculations seem to suggest that beam line shielding not necessary
  • goal: mitigate magnetic field - previously saw that after magnet have significant electron/positron striking beam pipe --> background from secondaries; now field is reduced and secondary contribution down as well, but perhaps can further improve
  • No significant changes in energy resolution, but do observe changes in position and angle resolution
  • Action Item: calculate background dose for general setting at small angle (6.3 deg) and at 3-4 m position - need new field maps for that


CRYSTALS

  • Received additional (64+50) Crytur crystals - total is now 464 Crytur crystals (no rejections)
  • Expect another 200 crystals in spring 2020
  • Contract for 250 Crytur crystals Sept 2020 - April 2021
  • Crystal article submitted to NIM journal


NEXT MEETING: THUR 16 JANUARY 2020 AT 9:00 AM (ET)

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