Optics Meeting Sep 3 2024 0100PM ET

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Agenda

1. (Chandan): reconstruction code update
2. (Kate): Visualizations of distorted magnetic field effect [1]

Attendance

David, Ciprian, Vassu, Kate, Sayak, Kate

Minutes

1. (Chandan, via David) Working on the GEM and fADC decoding classes for the MOLLER counting DAQ; at present, Chandan has the two main module decoding classes ready and is going to write other derived classes to have a septant-by-septant analysis. Has created a skeleton of a MOLLERSpectrometer class, which needs to be filled out by the optics experts to implement the optics matrix and get the vertex information from the GEM tracks. GitHub location of the current repository (it contains some working examples of GEM and fADC replay scripts): https://github.com/JeffersonLab/moller-counting
2. (Kate) See: [2] Generated simulations with Buddhika's field maps, and looked at the distribution of unscattered beam electron hits at a virtual detector (28) at the z-location of the main detectors, as a sanity check that the field maps are doing what is expected. Simulations are a million events with the beam generator, lH2 target; 4 hrs/file on ifarm. The maps are for various 1 mm shifts in the radial direction of magnet coil A (for upstream and downstream toroids) - Coil A is in the horizontal beam-left location. Shifts of +4 mm, +3, +2, +1, 0, -1, -2 mm (larger than we expect are reasonable, but this way can hope to get a good fit to the dependence. -1 mm file couldn't be analyzed (header file issue) but all others fine. Clearly see expected distprtions in location of these hits, smoothly varying as a function of coil shift. Suggestion: include virtual detector at the SAMs location, then can use Devi Adhikiri's scripts to extract ability of SAM data to see these distortions. Kate will contact Devi. Next steps: generate simulations with higher statistics and appropriate conditions, look at sieve hole signals on main detectors (virtual detector 28) and explore best signals for these coils shifts in those data. Kate has trained Evan Jackson (W&M senior undergrad) to run remoll simulations on the ifarm, and to generate CSV files and make simple plots of main detector hit patterns. Next simulations - start probably with pass3 on the most upstream 12C target (most likely to see largest fraction of sieve hole images), and also pass5 on lH2 target, both with standard sieve. Will later do sieve rotations.
3. (David) plan on a forthcoming, well-advertised optics meeting to review/discuss Vassu's kinematic factor algorithm.

Meeting link information

See email invitation, or contact David Armstrong, Kate Evans, or Ciprian Gal for Zoom link