Muon Beamlines & Delivery Ring Commissioning Progress
In July 2017, Jim Morgan oversaw the successful commissioning of muon beamlines and the delivery ring for the g-2 experiment. Significant milestones included maintaining the original schedule, achieving 85% beam time to the experiment, and addressing challenges such as mysterious losses and inefficiencies in the system. Despite some setbacks, progress was made in optimizing beam circulation and achieving successful beam deliveries to the g-2 Storage Ring.
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Presentation Transcript
Muon beamlines, Delivery Ring And g-2 Commissioning July 17, 2017 Jim Morgan
The good Successfully navigated Readiness Reviews in March Maintained original g-2 schedule of completing tunnel work by March 28 Began commissioning with beam on April 5 First turn in Delivery Ring and 8 GeV beam into M4 on April 27 Established circulating 8 GeV beam in Delivery Ring on May 6 Target station power supplies ready, secondaries into M2 on May 12 Delivered beam to the g-2 Storage Ring on May 22 (goal was June 1) Target Station dump installation completed June 8, intensity limit removed Commissioned many tools and sub-systems, including orbit programs, instrumentation and motion-controlled devices Improved Delivery Ring closed orbit with quad moves Demonstrated proton-removal works Installed BLM s in M4 and M5 M1 TLM measurements were made Delivered beam to g-2 for more than two months so that they were able to commission their Ring, kickers, inflector, electrostatic quads and detector subsystems
Beam to g-2 5.4 ~85% of the time POT directed towards beam to the experiment 2.5x10-8 muons per POT (simulation) at 25% efficiency ~9.7x108 muons to storage ring entrance (dp/p +/- 0.5%) Protons on target (E16) 3.6 1.8 0.0
The not so good 8 GeV M1 to M3 optics match is poor and beam sizes don t match model M1 toroids show mysterious RR to M1 inefficiency above about 3E11 Single 2.5 MHz bunch extractions from RR causes unacceptable losses in MI-8 dump region or RR dump, limiting the number of cycles Yield from Target Station is down 20 25%, spot size on target accounts for only ~10% Commissioning injection was much more difficult than it should have been, something may be wrong Mystery losses in M3 near Q711, Q725 and Q744, may be from obstacles or artifact of poor M1 to M3 8 GeV match Extraction was also difficult to commission, compounded by reversed horizontal motion-control readback on ELAM Straight-Through 3.1 GeV efficiency between IC740 in M3 and IC902 in M4 only about 60%, IC902 to IC025 also only 60% Delivery Ring 8 GeV circulating beam efficiency from end of M3 only 60% Delivery Ring 3.1 GeV efficiency very poor, only about 40% per turn
Straight-Through D30 to experiment Ion Chamber readbacks July 6 versus simulation (normalized to protons on target) Diktys simulation 1E12 POT July 7 Normalized to POT 3.4E11 POT Into M2 Line (IC804) 6.77E8 1.69E8 73% In downstream M3 Line (IC740) 2.12E8 5.03E8 70% In M4 Line (IC902) 1.16E8 0.47E8 41% End of M5 Line (IC025) 1.00E8 0.85E7 25% 2/17/2025 Jim Morgan
The not so good (cont.) Horizontal orbit closure wasn t achieved, efficiency very sensitive to horizontal orbit and bad orbits with 1-bumps improved efficiency Mystery loss in M5 near Q021 3.1 GeV proton secondaries to g-2 Ring causes rad trips that limit cycle time to ~0.1 Hz M5 points about 10mm left of Inflector entrance Beam leaks through extraction channel on first turn, sending undesired protons to g-2 in proton-removal mode Broke ASEP magnet somehow Some power supplies still not up to operational standards Struggled with instrumentation at times, BPM flash frame unreliable, some Ion Chambers and PWC s can t be remotely removed from the beam path Vacuum problems caused headaches (mostly from closed vacuum valves) Didn t make any progress towards fast cycle time 2.5 MHz bunches from RR need work, didn t try to get 1E12 per pulse
Rolled ISEP? +/- 1,000 A from nominal 17,800 A
The road ahead Proton removal has to work, otherwise can t run much beam to g-2 Delivery Ring 3.1 GeV efficiency has to be much better for proton removal to be effective Need to commission fast cycle time as early in fall as possible, otherwise number of cycles will be limited Poor efficiency in beamlines needs to be understood and corrected TOR750 should be relocated and replaced with large aperture toroid (TOR804?) Need to have better horizontal orbit control at the end of M3 and across DR injection 8 GeV M1 to M3 optics match problems an irritant for g-2, but will be a serious problem for Mu2e New septum magnets need to be installed during shutdown to be able to run at 12 Hz All apertures less than 4 need to be evaluated for possible removal, including and especially diagnostics in Delivery Ring Need to improve instrumentation before fall Unreliable flash frame, noise problems on SEM s and PWC s, inability to retract IC s and PWC s, vacuum leaks, etc. Need to stop closing vacuum valves (stop leaks ideal, otherwise jumper them) Need to get power supplies up to operational standards and have proper upper limits M5 alignment with respect to g-2 Ring has to be corrected Septum power supplies don t allow both 8 GeV operation and fast cycle time Have many problems, need to get more people involved in solving them
