General Meeting Summary 11/21/19

NPS COLLABORATION MEETING AGENDA

• Add item: assembly plan for frame (wrapping crystals, etc.)

• Assembly space: need place until run (full assembly with electronics, DAQ,...)

MAGNET

• Tests ongoing

PMT MAGNETIC SHIELDING

• Aims to protect PMTs when the calorimeter is close to the magnet and simultaneously keep material in front of the calorimeter at a minimum to not impact resolution.

• Concept: double shielding with mu-metal (inside) and iron (outside). The best shape is a box.

• Large magnet aperture as required for large solid angle - large flux that needs to be shielded. Shielding at magnet coils directly has no significant effect, so use a shielding box enclosure around the calorimeter.

• Primary flux can be removed with iron. 1 layer is standard, but here use two layers as default to reduce the field to below 0.2 G.

• Shielding for different configurations with field 0.6 T:

• at 4 meters: 2 mm iron in front and 1 mm at sides of Calorimeter
• at 3 meters: >~6 mm iron required (5 mm s not sufficient)

• Practically such additional shielding could be bolted on with a minimum number of bolts to minimize installation time (radiation consideration)

• Action Item: explicit calculations for 3 meters with field 0.3 T

FRAME

• In the process of procuring the final components/pieces

• Assembly is on schedule

• Meetings with engineers being planned around the NPS collaboration meeting

SIMULATION

• Energy and dose rate distribution discussion

• dose comes from higher energy parts - so can change magnet BdL, but not much impact since dose dominated by high energy
• From the plots one can see that in certain regions have less dependence on magnetic field
• Low energy particles dominate dose before the magnet, then remove e-/e+ and have only photons at low energy, high energy part not so simple to remove

• Action Item: Bogdan will send the latest magnetic field map to Ho San

HV DIVIDERS

• Table with available models and their measured resolutions and nonlinearities (3x3 prototype) being prepared

• Anode current measurements planned in Hall D

CRYSTALS

• Instrumentation paper to be posted soon

• Full NPS construction paper to follow

NEXT MEETING: THURSDAY 19 DECEMBER AT 9:00AM (ET)