GEn Analysis Meeting January 9 2025 10AM EST
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Agenda
- Roundtable (all)
Attendance
Arun, Jack, Hunter, Braian, Vimukthi, Dulitha, Gary, Bill, Sar, Bhasitha, Bogdon, Gordon, Andrew
Minutes
Gary talked about what is available in his thesis about the hodoscope and new calibration. Current calibrations are not final but they are improved.
Braian will get his tasks to start working on analysis in a more full fledged way
Hunter is working on polarimetry and hoping to finalize the results. He agreed to be the student point student for the mass replay. Arun asked what changes have been made. Hunter will show what is done and the target group will discuss error, beam depolarizations, convection speed knowledge, etc.
Gordon asked about being ready for pass 2 from a timing perspective. Andrew has some timing updates he showed at the GMn meeting implementing the internal alignment procedure in the hodoscope. The global fit does a good job of determining prop speed and time walk, but not as good at t=0. Andrew showed plots showing all corrections for hodo mean time vs. paddle number. These showed a very good internal alignment which should work well for each of the detectors in SBS. Andrew talked about documenting the procedure to clarify what is happening in the code.
Jack gave an update on LE timing being done for the next pass. There are only a handful of PMTs that are off, but nothing affecting the overall timing. THey are currently being fixed. Other work includes tightening the timing window for the GRINCH in an effort to better the track-matching. Other methods will also be implemented to see if improvements can be made.
Vimukthi talked about energy calibration work and alignment on the hadron arm side of the experiment. Should he try to fully calibrate SBS gems? He has done alignment but no other calibrations. Gain matching could be done, but every other calibration besides alignment is just improving efficiency and cleanliness of tracking. Talked about what constraints were good enough for GEN. Does Not need to delay the next pass.
Gordon still wonders about our understanding about how well we know the optics. We Have field map, generate a model. So the uncertainties come from the orientation of the gems and we have some uncertainty about the overall scale factor to the field map to match what we see in the data. Do low energy optics correlate to high energy? Andrew says it should work for all energies. Magnetic settings should change proportionally to the change in current, but the field map should remain proportional. Assume power supply jitter is very slow. Hysteresis effects are small for small changes in current percentage according to Bogdon. (0-100% has a large effect whereas 99-100% is small).
Arun asked if the changes made in the SBS software are now available so that the Trees are available for use. Andrew said there are new variables, and some meanings for variables may have slightly changed. Odef files should also be adjusted so the variables will be written to replays.
No meeting next week due to the Hall A collaboration meeting.
Meeting link information
See email invitation, or contact Arun Tadepalli for Zoom link.
