Simulations

Weekly Simulation Meetings

Simulation Tasks List

This is an estimated task list for all the subsystems

Task list by subsystems

This is to collect a complete list of simulation tasks for various subsystems. If you know the person working on a task please include the name in front of the task.

1. Spectrometer: collimation and magnetic coils (Juliette Mammei, Chandan Ghosh)
   1. Collimation optimization
   2. two bounce photon background optimization
   3. Radiation dose on coils and epoxy
   4. coil shielding
2. Target Area Shielding: (Nazanin Roshanshah, Weibin Zhang, Sakib Rahman, Chandan Gosh, Ciprian Gal)
   1. Optimizing the materials (cost reduction and decommission optimization )
   2. Accommodate for engineering access
      1. Balance reduced boundary dose with allowing sufficient room for assembly of target
      2. Reduce/remove shielding upstream of the target
   3. Determine radiation levels at the Moller polarimeter detector and Compton polarimeter locations
   4. Determine the optimal concrete, high-Z material mix to best contain radiation and reduce activation
3. Overall Radiation Shielding: (Ciprian Gal)
   1. optimizing backgrounds at the detector area
   2. optimizing backgrounds at the electronic huts
   3. optimizing backgrounds at the hall wall and roof
   4. optimizing backgrounds at the GEM electronic area
4. Activiation studies: (Rakitha Beminiwattha, ?)
   1. Radiation Cooling time estimates for hall access
   2. Radiation Cooling time estimates for target area access
   3. Activation at spectrometer
   4. Activation at collimators etc. after MOLLER completed for decommission
   5. Radioactive gaseous activation in the concrete
5. Main detector simulation: (Michael Gericke, Dustin McNulty)
   1. detailed detector simulation (qsim type)
   2. a cross-check on the detector area backgrounds
   3. Light from Al holding structure for quartz
   4. Light guide light generation.
6. SAM region simulation: (Dustin McNulty, Vassu Doomra, Ciprian Gal)
   1. Implement beamline in SAM region and determine effect on radiation levels
   2. optimizing backgrounds
   3. detector simulation (qsim type)
7. Pion Detector: (Wouter Deconinck, David Armstrong, Elham Gorgannejad, Raj Seehra)
   1. determine the detector size, placement, and local shielding within the current envelope that results in at last 10% pion signal relative to all backgrounds, both as measured by integration-mode photo-electron yield and by counting-mode events over a photo-electron threshold at the PMT
      1. determine the detector size, placement, and local shielding that results in at last 10% pion signal relative to all backgrounds as measured by particle count in the lucite volume
         1. establish an optimization procedure to determine detector size and placement to maximize the pion signal relative to all backgrounds as measured by particle count in the lucite volume
      2. determine the reflector and lightguide geometry that results in a number of photo-electrons that is above a detectable threshold (n_pe > 5) for any pion incident along z on any part of the lucite
         1. establish an optimization procedure to determine reflector and lightguide geometry to maximize the photo-electron efficiency for pions along z averaged over the lucite from face surface
   2. based on preliminary results under 1, determine by how much a lead donut thickness of 15 cm or 10 cm increases the rate of all backgrounds
   3. benchmark the detector simulation against detector prototype (consisting of a minimum of UVT lucite + reflector + PMT) cosmic ray measurements to reach 20% agreement in number of photo-electrons under at least 3 different reflector configurations
   4. develop a tentative pion detector run plan with anticipated integrated luminosities, asymmetry distributions and uncertainties, rate distributions and uncertainties, and a correction procedure for the main detector signal

Simulation To-Do List from Fall 2020

1. Envelope overlap with the coils: the 3 mm skin around the physical coils. Sakib showed some early results; we need to scrutinize them and make conclusions and see if there is further work to be done.
2. re-optimizing the real geometry for the tungsten merged col-1 2 and shielding around that area for US coils
3. reoptimize the upstream magnet area for the new radiation sources discovered (Positron shielding). Estimate radiation load on epoxy
4. The two bounce shield optimization: Review the downstream 2-bounce shield and optimize for radiation dose. This won't have to be a continuous tube and so will be easier to install.
5. Tweak Col-4
6. Col-5 optimization: revisit inner collimator 5 region and make a conceptual design that is buildable that also shields the “spokes” from getting into the physics region and also the SAM region
7. hybrid coil nose dose minimization and Estimate radiation load on epoxy
8. SAM donut design
9. Review what happens in the non-ideal case with a significant dipole field (in beamline??). Figure out the upper limit.
10. optimize the SAM donut and see if it can handle a similar dipole field.
11. a cross-check on the detector area backgrounds to make sure they didn’t get worse
12. Activation studies needed??: Bottleneck here is importing coil geometry. Great project for few undergrads.
13. Pion Detector Simulation

Simulation To-Do List from Summer 2020

1. Raster, position&angle offset sensitivities. -> Ciprian
2. Light guide light generation. Add this to the estimate of light generated from radiation getting to the PMT and confirm there is no impact on deconvolution analysis. ->KK's group
3. Develop benchmarks for single event upsets (in collaboration with Michael) -> Ciprian
4. SAM implementation and impact on radiation -> Chandan
5. Collimator 1&2 geometry change. I think Chandan has some work on this but we should establish some benchmarks to make sure we don't lose anything with the design change. -> Chandan
6. Target and Collimator 1/2 shielding updates (and potentially add beampipes and sieve locations). -> David K, KK, Ciprian, Chandan
7. Relax Detector Electronics bunker requirements.
8. Light from Al holding structure for quartz.
9. Col-5 Optimization

Simulation topics came up at the May 2020 Collaboration Meeting

1. Radioactive gaseous activation in the concrete
2. Is 8% of electrons from the air in front of the MD a concern
3. Do our simulations include thermalization in all the concrete in the hall and the thermals bathing the detector
4. Dump status and what needs to be added
5. PMTs made of borosilicate glass and the boron becomes very important with neutrons. We should put borosilicate if we haven't.
6. At PMT, if we got spallation from a neutron that could make a very big signal.
7. Are we plan to do some experimental validations using say a DT generator or neutron source (Cf, AmBe, AmLi)
8. Produce background rates in tables overall and in different regions
9. FLUKA geometry: We need to come up with a realistic simplified geometry for FLUKA starting from Sakib's latest "simplified" geometry and then adding the appropriate amount of relevant material
10. QA plots to be generated as part of simulation output for benchmark and version comparisons, etc.

Simulation Reference Documents

• Subsystem bounding boxes
• Detector ID assignments
• GitHub Tracking of Projects
• Target Region Shielding

Versions

• Next release: v2.1
• Following release: v2.2

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