[BTeam] Issues

[Mike Spata]

Good morning,

We had a discussion after the morning meeting about the present state of CEBAF performance. In general we were reacting to high trip rates and background in Hall B and Hall A Compton. The list is not exhaustive and I may have gotten something wrong. Yves and Dennis are on call and should carry this list of action to completion at a time that is agreed to by Ops Leadership, PD and Halls.

1. 0L04 Phase - we have a large stripe in the injection chicane with the bunch compression added which may be contributing to the large number of 0R08 BLM trips. Action: send beam to inline dump at program currents to assess trip rate at 0R08 BLM and perhaps put it back on crest.
2. 2E01, 2E02, 2E03 correctors are railed negative and the Dog 2 shunt is railed high which makes the middle dipole weak pushing the beam positive. These two things are fighting each other. Action: TIef sanity check and Ops should fix it.
3. Hall B quad settings relative to design - quads at top of ramp are 0 in EDT. Are the control system settings correct relative to the elegant lattice? We also have a long-standing 1.8% error in Hall B general transport quads in 2C relative to EDT. Action: Dennis to check settings of quads at ramp and feedback to B-Team for further discussion. The 1.8% error should be fixed during the long shutdown. Likely not causing halo issues in Hall B.
4. Should we be rotating Dog 1 in response to Dog 2 issues? Action: Tief to look at overall path-length management system to determine if there's anything we should be doing to normalize transport.
5. Compton counts relative to 0L04 phase and Hall A optics
6. NE shunt steering - was moved towards design but not all the way . We still have high radiation readings (1R/hr) at 3S01 quad. Action: Ops/B-Team decide if we should continue moving towards design when Hall C goes to 1st pass on Monday.
7. 2C15 ion pump is acting up. Are we generating Hall B halo from poor vacuum . Action: Ops to check archived signals to see if the period of good running in Hall B was during better performance from ion pumps in this segment.
8. 5th pass vertical separation settings - uncertain whether the phase and amplitude are truly set per standard operating procedure - Action: Ops should setup the line following the Extraction procedure and carry the setup all the way to the Hall dumplets with specific attention to using MBDAT05V to set the position of B&C on Lambertos and the BDs after Lambertson to pitch the C beam back parallel vertical transport.
9. We have had phase instability for the 1st pass separators - Action: Engineering to snoop for issues and Ops to check extraction settings after resolving railed correctors at 2E01, 2E02 and 2E03 and the Dogleg shunt issue. Should also confirm that the YA, BP and BQ settings as well as transport into Arc 2 are ideal.


Mike

--
Michael Spata
Deputy Associate Director
Accelerator Ops and R&D
Jefferson Lab
12000 Jefferson Avenue
Newport News, VA 23606
Cell: (757) 876-0528<callto:(757)%20876-0528>
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