Main Injector Gap clearing kickers

1. Main Injector Gap clearing kickers Phil Adamson

2. Increasing intensity for NuMI 11-batch slip-stacking MI Gap Clearing Kickers

3. Slip-stacking • Neutrino experiments want more beam! • Inject 11 batches rather than 6 • But pay for it with increased losses • (<95% efficiency) MI Gap Clearing Kickers

4. Slip-stacking recapture (real data) MI Gap Clearing Kickers

5. 3 losses, 1 cause • Uncaptured beam at start of ramp • Extraction losses caused by beam in extraction gap • Beam in injection gap – lost downstream of injection kickers MI Gap Clearing Kickers

6. Loss control in Main Injector • Avoid activation of tunnel components • ALARA • Uptime • Other loss mechanisms dealt with • MI-8 collimators • Scrape transverse tails before injection • MI-30 collimators • Lose uncaptured beam at collimators rather than Lambertsons • Fuzzer • Eliminate extraction loss by clearing beam from extraction gap at 8 GeV MI Gap Clearing Kickers

7. Longitudinal simulation for 11 batch slip stacking +40MeV 6 9 -40MeV 7 10 8 11 0 588 buckets MI Gap Clearing Kickers

8. Idea: Gap Clearing Kickers • Problem: beam gets into injection gap, sprayed in 104-105 region when kicker fires • Solution: build new kickers to send beam to abort instead • Kicker must have fast (3 bucket) rise and fall time to match injection kicker • But kick horizontally • In fact, requirements are almost identical to new NOvA RR injection kickers MI Gap Clearing Kickers

9. Magnets built by TD • Fast rise/fall time, so need short magnets • 7 magnets to generate necessary kick MI Gap Clearing Kickers

10. 2009 shutdown • Install magnets in tunnel MI Gap Clearing Kickers

11. It’s not just a few magnets • Kickers need power supplies, PFLs etc. • Kickers need to fire at 15Hz (or will in a few years time), so need temperature-controlled load • We didn’t have building space • Didn’t have penetrations for fluorinert piping • Didn’t have penetrations for HV cables • To get fast rise/fall time, need many small kickers, so need lots of all this MI Gap Clearing Kickers

12. 2009 shutdown • Dig up berm to find top of tunnel • Drill through (carefully) MI Gap Clearing Kickers

13. Then build a building MI Gap Clearing Kickers

14. …and outfit it MI Gap Clearing Kickers

15. 2010 shutdown • Complete tunnel work • Cables • Fluorinert • October 2010 • All kickers ready to go • Begin comissioning MI Gap Clearing Kickers

16. GCK beam hits the dump • Abort • GCK MI Gap Clearing Kickers

17. Kicker measurements • Inject beam into MI, fire kicker through it • Use MI damper to get bunch-by-bunch position measurement • Fit turn-by-turn data MI Gap Clearing Kickers

18. Rising and falling edges • Edges within specification • Slower edge in damper measurement might be measurement artifact Damper (beam) measurement Calculated B from measured voltages MI Gap Clearing Kickers

19. Kicker tail • For recycler, building “tail bumper” to cancel tail • Tail measurement similar to electrical measurements (good) MI Gap Clearing Kickers

20. After NuMI returns Kickersoff MI Gap Clearing Kickers

21. After NuMI returns Kickerson. Circled loss due to steering error (later corrected). MI Gap Clearing Kickers

22. Beam loss, 104-106 region GCK on GCK on 11-batch slip-stacking MI Gap Clearing Kickers

23. Loss and activation Green points: contact measurement at V105 GCK on for a week MI Gap Clearing Kickers

24. Increased beam power • Reached 400 kW in Main Injector • Looking forward to NuMI’s return 401 kW MI Gap Clearing Kickers

25. Gap-Clearing Kickers: a successful AD/TD collaboration • AD (power supply and vacuum components) • Christine Ader • Rob Reilly • Chris Jensen • George Krafczyk • Jim Biggs • Steve Ward • plus 12 technicians • TD (magnets) • George Velev • IouriTerechkine • Bob Jensen • Bill Robotham • Ollie Kiemschies • plus 5 technicians MI Gap Clearing Kickers

26. The remaining loss spike • Opened up 113 location last week • Found problem MI Gap Clearing Kickers