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Status of Current High Power Proton Drivers for Neutrino Beam

Status of Current High Power Proton Drivers for Neutrino Beam. Yoichi Sato Main Ring commissioning group, J-PARC/KEK 2017/9/25 MON 11:00-11:30 NUFACT2017, Uppsala University, Sweden. Outline. Current status of J-PARC accelerators for T2K project

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Status of Current High Power Proton Drivers for Neutrino Beam

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  1. Status of Current High Power Proton Drivers for Neutrino Beam YoichiSato Main Ring commissioning group, J-PARC/KEK 2017/9/25 MON 11:00-11:30 NUFACT2017, Uppsala University, Sweden

  2. Outline • Current status of J-PARC accelerators for T2K project • Current status of FNAL accelerators for NOvA project

  3. Current status of J-PARC accelerators for T2K project

  4. J-PARCAccelerators Main Ring (MR) Circumference 1567.5 m Three-fold symmetry Imaginary Transition γ lattice Injection Energy 3GeV Extraction Energy 30 GeV • FXBeam Power • 470 kW (Present) • 750 kW (Design) • Keys • Beam Loss Localization • Less radioactive • High Intensity Proton Accelerators • Facilities to use the secondary beams • Operated by Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK) Main Ring (MR) [30 GeV] Rapid Cycling Synchrotron (RCS) [3 GeV] Hadron Hall Material and Life Science Facility (MLF) LINAC [400 MeV] Slow extraction mode (SX) for the hadron hall: 2 s spill extraction in 5.52 s cycle. NeutrinoFacility Fast extraction mode (FX) for the neutrino Facility: 1 turn extraction in 2.48 s cycle.

  5. Typical OperationStatusforFX MR power 473 kW (4 batches = 8 bunches) w MR loss 800 W Monitor sensitivity×8 Accel. 2.48 sec cycle Injection Extraction Most of non-COL area: One foot < 300 uSv/h (4H after operation) On contact < 2 mSv/h (6H after operation) 2 bunches at each injection Time (s) • Present beam loss 800 W < COL capacity: 2.5 kW • Beam losses are mostly localized at the collimator section. • Hands-on maintenance is possible with minimum exposure of residual radiation. • We can use COL capacity effectively even in faster cycle (2.48s -> 1.28s) , near future Acceleration Recovery Injection 0.01 + 0.13 s 0.94 s 1.4 s

  6. MRBeamPowerHistory • The beam power of 470 kW has been recently achieved with 2.44×1014 protons per pulse (ppp) and the cycle time of 2.48 s. 511 kW was successfully demonstrated. • The designed beam power of 750kWwillbeachievedbymakingthecycletimeshorter(1.3 s)andwith2×1014ppp. • The milestone for the number of accelerated protons has already been passed. 470 kW 410 kW FX Beam stop due to the radioactive material leak incident in HEF Beam stop due to the earthquake SX

  7. Operationat the New Betatron Tune Theoperationtune has been changedfrom(22.40,20.75)to(21.35,21.45)for the operation of > 420 kW. • Fine tunings of • Injection beam tunings • Optics correction • Resonance correction • 2nd harmonic RF • IntraBFB / Chrom / RF • Collimator balance • and so on • --- SAME procedures • established by 2016 Spring (21.35, 21.45) (22.40, 20.75) • Space charge tune spreads for MR 380 kW equiv. are shown. • Structure resonances of up to 4th order (Solid lines) • Non-structure resonances of half integer and linear coupling resonances (Dashed lines)

  8. Space Charge Tune Spread 500 kW νx−νy=0 2νy=43 21.5 • MR Power 500 kW • MR Cycle: 2.48 s • Number of protons: 3.2e13 ppb • Transverse Emittances • H: 15π mmmrad • V: 19π mmmrad • Bunching Factor: 0.3 • Bf = Average / Peak in beam current • Space Charge Tune Shift: 0.4 νx−2νy=−21 νx+2νy=64 • Injection beam tunings • 2nd harmonic RF • Optics correction • Resonance correction νy=21 21.0 • E = 3 GeV • (v/c)2γ3=69.751 • 2RN = 3.210139 : Intensity • 42/ = 17mmmrad : Emittance • Bf = 0.3 : Bunching factor 21.5 21.0 νx+νy=42 3νx=64 2νx=43 νx=21

  9. 2nd Harmonic RF Operation Fundamental 100 kV 2nd harmonic 70 kV Bunching factor 0.3 ~ 0.4 Bunch length ~400 ns Fundamental 100 kV 2nd harmonic 0 kV Bunching factor 0.2 ~ 0.3 Bunch length ~200 ns Simulation (100 kV, 70 kV) Simulation (100 kV, 0 kV) • RF Pattern for operation: • Injection : • 180 kV (fundamental), • 110 kV (2nd harmonic) • Acceleration : • 300 kV → 256 kV (fundamental)

  10. Beta Modulationbytheleakfieldof FXseptummagnets and Correction • Leak field of 8 FX septum magnets corresponds to ~3% of K1 of the nearest main Q magnet. • Modulations were observed for both horizontal and vertical beta in the beginning of acceleration. • Trim coils of 3 Q magnets have been used to correct the leak field of FX septum magnets. • The beam loss was reduced with the adjustment.

  11. Correction of the 3rd Order Resonances of both νx+2νy = 64 and 3νx = 64 νx−νy=0 2νy=43 21.5 • Trim coils of 4 sextupole magnets are used to correct of both νx+2νy = 64 and 3νx = 64. • Remanent fields of resonance sextupole magnets (RSX) for SX are part of the source of the third order resonances.  We have degaussed the RSXs. • Beam losses were reduced with the correction during injection and the beginning of acceleration. νx−2νy=−21 νx+2νy=64 νy=21 21.0 • Equations for canceling both resonances, for k2(1), k2(2), k2(3), k2(4). • 1 = SFA048, 2 = SFA055, 3 = SFA062, 4 = SFA069 21.5 21.0 νx+νy=42 3νx=64 2νx=43 νx=21 Injection Acceleration

  12. Suppression of the Beam Instabilities • Negative chromaticity is applied for the instability suppression. Typically −6 during injection. • Bunch by bunch feedback and intra-bunch feedback systemare used during injection. • Intra-bunch FB is successfully applied up to 0.12 s after the beginning of acceleration. Bunch by bunch feedback system Intra-bunch feedback system (wideband) Beam Position with Intra-bunch FB off Beam Position with Intra-bunch FB on 2.1e13 ppb × 2 bunches P1+100 ms P2 P1+100 ms P2

  13. High Intensity Beam Study • Betatron tune (21.35, 21.45) • 2nd harmonic rf High Gain =Low Gain x8 Extracted beam : 2.64 e14 ppp Total beam loss ~ 1.7 kW The MR has capability to achieve >1MW with the high repetition rate operation.

  14. Fermilab Current status of FNAL accelerators for NOvA project

  15. 700 kW operation for Long baseline neutrino experiment Numi(120GeV) LINAC 400 MeV Recycler(RR) 8 GeV Main Injector (MI) 120 GeV Booster 8 GeV Kiyomi Seiya, HINT2016

  16. 2017 Accelerator performance met goals Goal Goal Minimum requirement Minimum requirement Running above 700 kW to NuMI and its peak power 727 kW 630 kW when 10% of timeline to SY120 fixed-target program Final modifications for new Booster shielding assessment (up to 2.7x1017 protons per hour) were put in place in this March. http://www-bd.fnal.gov/FixedTargetPlots/today/ProtonPlots.html

  17. Main Injector (MI) and Recycler Ring (RR) Recycler (RR): 8GeV fixed energy storage ring with permanent magnets. Main Injector (MI): 8GeV –120GeV 400kW: Booster MI 700kW: Booster  RR MI Kiyomi Seiya, HINT2016

  18. 400kW to 700kW operation for Numi Jeffrey Eldred, Dissertation 2015 Injection & Slip stacking (0.8 sec for 12 batches) 11 booster batches every 2.2sec Momentum in MI Int. RR Int. MI 400kW 1.6 sec 12 booster batches every 1.33sec Int. Booster 700kW 1.33 sec Kiyomi Seiya, HINT2016

  19. MI Beam power and beam delivery to NuMI 6+6 SS MI Beam Power and Beam Delivered since the ANU Shutdown 4+6 SS 2+6 SS RR OPERATIONAL MI ONLY S. Nagaitsev

  20. Booster / Notch creation Longitudinal profile monitor @ Booster injection h=588 Main Injector / Recycler 1 Booster revolution • Notch • 81 bunches • + 3 empty bkts Gap for the extraction kicker capture with 37MHz RF  84 bunches h=84 Time Injection 200MHz 81 bunches + 3 empty buckets Notch(extraction kicker gap) – Booster extraction kicker –MI/RR injection kicker Notch has to be created at LOW energy Kiyomi Seiya, HINT2016

  21. LINAC Notch WCM signal in Booster injection period and 1st turn after injection 1 revolution Beam sent to the Booster with Laser • Laser notching cavity installed on the downstream RFQ flange in order to remove electrons from H- ions in proper timing. • Commissioning started at the end of November 2016. Kiyomi Seiya, HINT2016

  22. Linac laser notcher and loss reduction in Booster To Recycler for NuMI To Recycler for NuMI BNB Laser off Laser on collimators injection Booster intensity Booster extraction losses absorber for Booster notching extraction BNB Laser notch Laser on Laser off Laser on S. Nagaitsev

  23. Recycler collimators and new damper (reduce/control loss) Secondary Mask • Bunch-by-bunch damper didn’t work when bunches overlapped during slipstacking • Implemented diode frequency damper • Instabilities suppressed • No longer need for high chromaticity during slipstacking • Reduced losses from tune shift Collimators installed in FY16 shutdown BEFORE AFTER Abort Injection Ext. Numi address FY17 shutdown Collimators New collimator S. Nagaitsev

  24. Summary • High power protons have been provided from J-PARC Main Ring for T2K project, and from Fermilab Main Injector for NOvA project. • J-PARC MR in FX: 470 kW stable operation, 511 kW demonstration. • Fermilab MI to NuMI: 700 kW stable operation, 727 kW peak.

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