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The BNL Super Neutrino Beam Project

The BNL Super Neutrino Beam Project. W. T. Weng Brookhaven National Laboratory APS April Meeting ( T13 ) Tampa, Florida April 18, 2005. A. AGS Operation with protons B. Super Neutrino Beam Facility (1MW) B.1. New 1.2 GeV SCL B.2. AGS System Upgrade B.3. Neutrino Beam Production

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The BNL Super Neutrino Beam Project

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  1. The BNL Super Neutrino Beam Project W. T. Weng Brookhaven National Laboratory APS April Meeting ( T13 ) Tampa, Florida April 18, 2005

  2. A. AGS Operation with protons B. Super Neutrino Beam Facility (1MW) B.1. New 1.2 GeV SCL B.2. AGS System Upgrade B.3. Neutrino Beam Production C. Cost Estimate and Schedule D. Further Upgrade Possibilities E. Conclusion OUTLINE

  3. AGS Intensity History 1 MW AGS

  4. Transition Time to Restore HEP

  5. AGS high intensity/RHIC operation • AGS high intensity operation when RHIC is at store. • RHIC at store: presently ~ 85 hrs/week (50%), goal: ~ 100 hrs/week (60%) • Au – Au: • Typical 4-hour store length determined by Intra-Beam-Scattering (IBS) • With future luminosity upgrade (RHIC II) 4-hour store length determined by “burn-off” • Minimum refilling time is 5 – 10 minutes, typically takes < 1 hour • Fast injector switching between RSVP and RHIC mode beneficial • p – p: • Typical store length: 8 – 10 hours • Slower injector switching possible and necessary to ramp super-conducting AGS Siberian snake • Only incremental costs for high intensity operation. • High intensity and RHIC operations is very beneficial for equipment reliability and development of expertise.

  6. To RHIC To Target Station High Intensity Source plus RFQ 200 MeV Drift Tube Linac BOOSTER AGS 1.2 GeV  28 GeV 0.4 s cycle time (2.5 Hz) 200 MeV 400 MeV Superconducting Linacs 800 MeV 1.2 GeV 0.2 s 0.2 s AGS Upgrade to 1 MW • 1.2 GeV SCL extension for direct injection of 8.9  1013 protonslow beam loss at injection; high repetition rate possible. • 2.5 Hz AGS repetition ratetriple existing main magnet power supply and magnet current feeds, double rf power and accelerating gradient.

  7. 1.2 GeV SCL Typical DTL cycle for Protons 0.4 sec 0.4 sec 1 x 720 µs @ 30 mA AGS 0.6 sec 2.4 sec Booster 1.5-GeV Booster 28-GeV AGS 200-MeV TDL HI Tandem Two Injection Schemes

  8. AGS Proton Driver Parameters • present AGS 1 MW AGS J-PARC • Total beam power [MW] 0.14 1.000.75 • Injector Energy [GeV] 1.51.2 3.0 • Beam energy [GeV] 24 28 50 • Average current [mA] 6 3615 • Cycle time [s] 2 0.4 3.4 • No. of protons per fill 0.7  1014 0.9  1014 3.3  1014 • Ave. circulating current [A] 4.2 5.0 12 • No. of bunches at extraction 6 23 8 • No. of protons per bunch 1  1013 0.4  1013 4  1013 • No. of protons per 107 sec. 3.5  1020 23  1020 10  1020

  9. Layout of the 1.2 GeV SCL

  10. 1.2 GeV Superconducting Linac • Beam energy 0.2  0.4 GeV 0.4  0.8 GeV 0.8  1.2 GeV • Rf frequency 805 MHz 1610 MHz 1610 MHz • Accelerating gradient 10.8 MeV/m 23.5 MeV/m 23.5 MeV/m • Length 37.8 m 41.4 m 38.3 m • Beam power, linac exit 17 kW 34 kW 50 kW Based on SNS Experiences

  11. AGS Upgrade with CCL & SCL To RHIC To Target Station High Intensity Source plus RFQ 200 MHz DTL 800 MHz CCL BOOSTER AGS 1.2 GeV - 28 GeV 0.4 s cycle time (2.5 Hz) 116 MeV 400 MeV 800 MHz Superconducting Linac 1.5 GeV 0.2 s 0.2 s • Add CCL from 116 MeV to 400 MeV • SCL from 400 MeV to 1.5 GeV at 25 MeV/m gradient • One type of cavity, cryomodule, and klystron, similar to SNS.

  12. B.2. AGS System Upgrades • Beam Dynamics in the AGS • Injection Painting • Linac Emittance improvement • Transition Crossing • Ring Impedances • Beam Collimation and Shielding • AGS Magnet Test • New Power Supply Design • AGS RF Cavity Design

  13. Loss Limit & Estimate Losses

  14. Beam Loss at H- Injection Energy • AGS Booster PSR LANL SNS 1 MW AGS • Beam power, Linac exit, kW 3 80 1000 50 • Kinetic Energy, MeV 200 800 1000 1200 • Number of Protons NP, 1012 15 31 100 100 • Vertical Acceptance A, pmm 89 140 480 55 • b2g30.57 4.50 6.75 9.56 • NP / (b2g3 A), 1012 / pmm 0.296 0.049 0.031 0.190 • Total Beam Losses, % 5 0.3 0.1 3 • Total Loss Power, W 150 240 10001440 • Circumference, m 202 90 248 807 • Loss Power per Meter, W/m 0.8 2.7 4.0 1.8 • ( Contro & Uncontrol )

  15. AGS Injection Simulation • Injection parameters: • Injection turns 360 • Repetition rate 2.5 Hz • Pulse length 1.08 ms • Chopping rate 0.65 • Linac average/peak current 20 / 30 mA • Momentum spread  0.15 % • Inj. beam emittance (95 %) 12 p mm • RF voltage 450 kV • Bunch length 85 ns • Longitudinal emittance 1.2 eVs • Momentum spread  0.48 % • Circ. beam emittance (95 %) 100 p mm

  16. Halo in AGS as Function of Linac Emittance For acceptable operation, the linac emittance has to be less than 1.5p

  17. Linac Emittance Improvement Emittance at source 0.4 pi mm mr (rms,nor)

  18. AGS New Transition Crossing • RF system: h=6 -> h=24; • (+) High acceleration rate: dB/dt increased from 2.2 to 7.2 T/s • (-) A large momentum spread is an issue – a result of the high RF voltage and large bunch area • Tolerable beam loss is about 0.25% at transition • The initial 95% bunch area needs to be reduced below 0.8 eVs

  19. Expected transition loss vs. bunch area

  20. New AGS Main Magnet Power Supply • presently: • Repetition rate 2.5 Hz 1 Hz • Peak power 130 MW 50 MW • Average power 2.7 MW (FEB) 4 MW (SEB) • Peak current 5 kA 5 kA • Peak total voltage  25 kV  10 kV • Number of power converters / feeds 6 2

  21. Eddy Current Losses in AGS Magnets For 2.5 (5.0) Hz: In pipe: 65 (260) W/m In coil: 225 (900) W/m

  22. AGS RF System Upgrade • Use present cavities with upgraded power supplies • UpgradePresent • Rf voltage/turn 1.0 MV 0.4 MV • RF voltage/gap 25 KV 10 KV • Harmonic number 24 6 (12) • Rf frequency 9 MHz 3 (4.5) MHz • Rf peak power 2.7 MW 0.75 MW • Rf magnetic field 18 mT 18 mT • 300 kW tetrodes/cavity 2 1 • AGS/RHIC Operation Pulse-to-Pulse Same RF System modulation

  23. B.3 Neutrino Beam Production • 1 MW He gas-cooled Carbon-carbon target • New horn design • Target Hill for Radiation Protection • Target on 11.3 degree down-hill slope to aim at Homestake mine • Beam dump well above ground water table to avoid activation • Near Detector Beam Monitoring

  24. Transient temperatures in the CC target subjected to a 100 TP, 28GeV 2mm RMS beam. Coolant temperature in the annular space The = 5 degree C

  25. E951 Results: ATJ Graphite vs. Carbon-Carbon CompositeThe results demonstrate the superiority of CC in responding to Beam SHOCK.The question is: Will it maintain this key feature under irradiation ???We will find out in the course of this irradiation phase

  26. Super-Invar Irradiation Study – CTE assessment Super-Invar

  27. PHASE-II TARGET MATERIAL STUDY WHAT’S NEXT ? PERFORM irradiation and assess mechanical property changes for a host of baseline materials. Perform more sophisticated assessment • Carbon-Carbon composite • This low-Z composite gives the indication that it can minimize the thermal shock and survive high intensity pulses. • Because of its premise it is the baseline target material for the BNL neutrino superbeam initiative. • The way its key properties (such as CTE or strength) degrade with radiation is unknown. • Titanium Ti-6Al-4V alloy • The evaluation of the fracture toughness changes due to irradiation is of interest regarding this alloy • that combines good tensile strength and relatively low CTE • Toyota “Gum Metal” • This alloy with the ultra-low elastic modulus, high strength , super-elastic like nature and near-zero linear expansion • coefficient for the temperature range -200 oC to +250 oC to be assessed for irradiation effects on these properties. • VASCOMAX • This very high strength alloy that can serve as high-Z target to be evaluated for effects of irradiation on CTE, • fracture toughness and ductility loss • AlBeMet • A low-Z composite that combines good properties of Be and Al. Effects of irradiation on CTE and mechanical • properties need to be assessed • TG-43 Graphite • Possibly Nickel-plated Aluminum T6061 (Horn material) for visible irradiation/corrosion effects, loss of electrical conductivity, delamination, etc.

  28. WHAT IS OF INTEREST TO US IN POST-IRRADIATION PHASE • Resilience in terms of strength/shock absorption • CTE evaluation • Stress-strain • Fatigue • Fracture Toughness and crack development/propagation • Corrosion Resistance • De-lamination (if a composite such as CC or plated HORN conductor) – Use of ultrasonic technology to assess changes • Resistivity changes • All of the above can/will be done in Hot Cell. • Other tests are also in the planning for scrutiny of the successful candidates (laser induced shock and property measurements)

  29. Super Neutrino Beam Geographical Layout Super Neutrino Beam Geographical Layout  BNL can provide a 1 MW capable Super Neutrino Beam  the neutrino beam can aim at any site in the western U.S.; the Homestake Mine is shown here  there will be no environmental issues if the beam is produced atop the hill illustrated here and the beam dumped well above the local water table  construction of the Super Neutrino Beam is essentially de-coupled from AGS and RHIC operations

  30. Neutrino Spectrum at 1 km Low Z (Carbon) target seemsfeasible for 1 MW, 28 GeV proton beam. Thin low Z target minimizesreabsorption which increases flux of high energy neutrinos

  31. Homestake BNL 2540 km BNL  Homestake Long Baseline Neutrino Beam Baseline Design: • 28 GeV protons from the AGS • 1 MW beam power from upgraded proton driver • 500 kTon Water Cherenkov Detector • Conventional Horn Focused beam • Alternate detector sites such as the WIPP facility in New Mexico and the Henderson mine in Colorado would be acceptable. The Homestake site is used for purposes of calculation.

  32. Preliminary Cost Estimate – Continued • Total Direct Cost=$274 M • Add: • Contingency, 30% • BNL Project Overhead, 14.5% • Total Estimated Cost = $407 M

  33. Construction Schedule

  34. D. Further Upgrade Possibilities • Several possible upgrades, if combined, can provide 2 MW beam. • Increase the AGS repetition rate beyond 2.5 Hz. This can be accomplished by ramp down the AGS magnet in 0.1 sec, a • combined rep rate of 3.3 Hz. • Increase the AGS intensity to 1.3 x 1014 protons per pulse. To make this option possible, the SCL energy has to be increased to be 1.5 GeV. A better transition crossing system has also to be implemented. • A longer decay tunnel for capturing neutrino beam. • An improved hardonic beam focusing system

  35. E. Conclusions • The feasibility has been demonstrated for a 1MW upgrade for the AGS • It is possible to further upgrade the AGS to 2 MW • Active R&D efforts are in progress to improve on the design and reduce cost. • The Total Estimated Cost is 407 M$ to complete the AGS upgrade and neutrino beam delivery system. • The construction can be completed in 5 years, with several years R&D efforts.

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