AIOP Nov. 4, 2024

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AIOP - Polarized Photon Source

Agenda:

1. Previous Meeting

2. Announcements

3. Conferences/Workshops
   • ICFA Beam Dynamics Mini-Workshop on Machine Learning for Particle Accelerators (Apr. 8-11 CERN)

4. Project Progress
   • Coherent peak drift evidence
   • GitHub AIOP Project (AIOP-Photon issues)
   • Milestones: PDF(GitHub AIOP Project AIOP-Photon issues FTE Profiles)

5. PIER Activities
   • Middle School Data Science Hackathon Workshop (Oct. 16)
     • Flappy Bird RL Learning
   • HUGS mini-Workshop - COMPLETED!

6. AOT

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Minutes

Attendees: Naomi J., Patrick M., David L., Jiawei G., Torri J., Armen K.

• We noted that the next Hall-D beam time is scheduled for end of Jan. or early Feb. It will use the coherent photon source.
  • We will not have anything in place by then, but should aim to have something to test before the end of the Run
  • Naomi noted that we should make sure to record the target beam positions and coherent edge position from the white board during the run.
  • David said he would contact Hovanes about the possibility of saving all of the images of the whiteboard instead of deleting older ones.

• Jiawei showed several slides looking for correlations between beam position or angle and the coherent edge position
  
  • The most probable value of the coherent edge movement between the beginning and end of nudge sequence is 0. This is confusing since it implies a large fraction of nudge sequences resulted in no changes which begs the question of why the shift worker felt compelled to nudge in the first place.
  • There were a couple of small peaks at 1mm in y and 0.5mm in x. Naomi reminded us that Hovanes thought these were due to the beam being off and registering as being at 0,0.
    • We suggested Jiawei use Myaplot to show the beam current in the vicinity of a few nudge events to confirm that beam trips are not the cause.
  • Jiawei showed plots that included the change in total difference in distance between the Active Collimater position and 5C11B position. This should be related to any angle change in the beam.
    • Correlation plot showed no significant correlation with the coherent edge
  • We discussed what other possible causes there could be for the coherent edge to drift.
  • Naomi again reminded us that Hovanes speculated last time that the backlash in the goniometer might be significant enough as to cause non-reproducibility in the angles.
  • Naomi also pointed out the GlueX Demon web page that has some plots where asymmetries are shown as a function of time, and there are clear places where this fluctuated at certain diamond orientations.
    • We decided a good next step would be to focus on some of these points where a large effect is seen. Naomi was going to show Jiawei how to get the correct data and he will extract it into the standard form.

• Patrick showed a slide where he went back to the Lohman paper that the Livingston paper references. He pulled out a formula for the coherent peak to beam ratio as a function of the beam to crystal angles theta and alpha.
  • He showed that he was able to calculate the Epeak vs. c-angle correlation values using this.
  • We discussed some whether we could extract the angle offsets from the data itself. We decided that if the backlash issues is real, it may prevent this.
  • Patric was going to investigate whether the backlash issue exists.

Action Items

• Enable archiving of whiteboard images permanently (David/Hovanes)
• Extract anomalous points from 2023 dataset (Jiawei/Naomi)
• Investigate backlash issue in goniometer (Patrick)