Photon Beam Commissioning Discussion July 7, 2014
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Contents
Organization
- Time: 4 pm EST
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References
Agenda
- Announcements
- Electron Commissioning (Todd/Mike)
- Photon Commissioning Draft (Eugene)
- Goals for Aug 8 Review
- Other business
Minutes
- Attending: Elton, Eugene, Alexandre, Sasha (Hall D); Mike McCaughan, Todd Satogata (Accelerator); Richard (UConn); Curtis (CMU).
- Announcements
- Electron Commissioning (Todd/Mike)
- 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
- 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 .
- Radiators
- Production radiators are (10^-5, 3x10^-4, 10^-3)
- Propose the following set for commissioning: (3x10^-5, 10^-4, 3x10^-4)
- Mike detailing procedures for commissioning electron beam based on experience in April
- Photon Commissioning Draft (Eugene)
- 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
- Discussion of draft plan submitted as homework to ERR
- Goals for Aug 8 Review
- Other business