Photon Beam Commissioning Discussion July 7, 2014

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Organization

  • Time: 4 pm EST
  • Connecting: detailed instructions are here
  • Conference id: 536076821

References

Agenda

  1. Announcements
  2. Electron Commissioning (Todd/Mike)
  3. Photon Commissioning Draft (Eugene)
  4. Goals for Aug 8 Review
  5. Other business

Minutes

  • Attending: Elton, Eugene, Alexandre, Sasha (Hall D); Mike McCaughan, Todd Satogata (Accelerator); Richard (UConn); Curtis (CMU).
  1. Announcements
  2. Electron Commissioning (Todd/Mike)
    1. Mike detailing procedures for commissioning electron beam based on experience in April
      • Much learned from beam delivery
      • Confidence that delivery this fall will be clearner
      • Expect: days to tune after spinning up to 5.5 pass; reasonable radiation without radiator
      • Initial goal for emittance is 20 nm*rad x 2. [Design is 25 nm*rad in x and 10 nm*rad in y]
      • Setup beam so that virtual focus of electron beam is at the collimator
      • Need to characterize the ion chambers (minimizing scrapping and tails)
      • nAmp bpms should be installed, but operation is not needed for commissioning
      • Fast feedback is also not critical
    2. Simulation of beam environment
      • Richard will provide a geometry for Todd to run simulations
      • Richard will include the mapped tagger magnetic field
      • Todd will provide a magnetic field for the quad immediately upstream of the tagger magnet.
      • (Eugene) Suggest to have the quad off during initial commissioning.
      • Check that RadCon detectors can be borrowed to measure rates in tagger hall and Hall D. Alexandre is working with Melvin Washington to arrange this.
    3. Radiators
      • Production radiators are (10^-5, 3x10^-4, 10^-3)
      • Propose the following set for commissioning: (3x10^-5, 10^-4, 3x10^-4)
  3. Photon Commissioning Draft (Eugene)
    1. Discussion of draft plan submitted as homework to ERR
      • Eugene summarized the procedure and discussion of various items followed
      • Update plan with radiators for commissioning
      • Goal is to use cw at 50 nA, but have a backup plan in case tune beam is needed
      • Likely use 5 mm collimator hole instead of 3.4 mm. (Can active collimator be mounted on either hole?)
      • Use photon profiler to initially determine position of beam on face of collimator
      • Scan photon beam with correctors immediately upstream of tagger magnet to determine/verify sensitivity of position to current in correctors
      • Possibly move profiler to location near the target. This would require a location with known position (surveyed) relative to target/beamline.
      • Use active collimator to verify that photon beam is centered on collimator hole. (Richard) This should be able to done even before active collimator is calibrated.
      • Discussion of fabricating a small calorimeter detector, as backup, to sit behind one of the collimator holes to check amount of beam passing through the hole.
      • (Sasha) During initial beam position calibrations, have the secondary collimator inserted to minimize scrapping background in the hall.
      • Rapid access system to be installed in Hall D. Need to make sure that the system is being implemented.
  4. Goals for Aug 8 Review
    • Organize as an unofficial review of beamline procedures
    • Invite Mike Spata and Brian Freeman from accelerator and Stepan Stepanyan (or Andi Sandorfi) from Hall B to be reviewers
    • Talks: photon beam production and characteristics (Richard); electron beam commissioning (Todd); photon beam commissioning (Alexandre?); do we need one on controls? radcon?
    • Pre-brief materials: Beam specifications; Hall D / accelerator coordination documents; electron beam commissioning procedures; photon beam commissioning procedures; draft sequence of commissioning
  5. Other business
    • Next meeting next week Jul 16 at 4 pm.