General Meeting Summary 12/19/19

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)