DESIGN OF THE BNL SUPER NEUTRINO BEAM FACILITY

1. DESIGN OF THE BNL SUPERNEUTRINO BEAM FACILITY W. T. Weng Brookhaven National Laboratory Neutrino Super Beam, Detectors and Proton Decay BNL/UCLA/APS Workshop March 3-5, 2004, BNL

2. AGS Operation with protons Accelerator Upgrade (1MW) R&D Activities Accelerator System Cost Estimate Further Upgrade Potential Conclusion OUTLINE

3. AGS Intensity History 1 MW AGS

4. 1.2  1020 1.0  1020 0.8  1020 Total accelerated protons 0.6  1020 0.4  1020 0.2  1020 0 Total Accelerated Protons at the AGS Slow extracted beam (Kaon decay) Fast extracted beam (g-2) Note: Lower total accelerated protons in later years due to much shorter running time

5. Transition Time to Restore HEP

6. Concurrent HEP Operation with RHIC • From the performance data shown, it is clear that it is possible to operate AGS proton-based HEP research in concurrence with RHIC operation. • The available AGS HEP running is about 80% of the total RHIC operation time. • The HEP program only have to pay for incremental costs, which is a big savings from independent operation. • The co-existence of HEP and RHIC operations is very beneficial for both equipment reliability and personnel training.

7. 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 superconducting linac extension for direct injection of ~ 1  1014 protonslow beam loss at injection; high repetition rate possible further upgrade to 1.5 GeV and 2  1014 protons per pulse possible (x 2) • 2.5 Hz AGS repetition ratetriple existing main magnet power supply and magnet current feeds double rf power and accelerating gradient further upgrade to 5 Hz possible (x 2)

8. 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 AGS Upgrade

9. AGS Proton Driver Parameters • present AGS 1 MW AGS2 MW AGS J-PARC • Total beam power [MW] 0.14 1.002.000.75 • Injector Energy [GeV] 1.51.21.5 3.0 • Beam energy [GeV] 24 28 28 50 • Average current [mA] 6 367215 • Cycle time [s] 2 0.4 0.4 3.4 • No. of protons per fill 0.7  1014 0.9  1014 1.8  1014 3.3  1014 • Average circulating current [A] 4.2 5.0 10 12 • No. of bunches at extraction 6 24 24 8 • No. of protons per bunch 1  1013 0.4  1013 0.8  1013 4  1013 • No. of protons per 107 sec. 3.5  1020 23  1020 46  102010  1020

10. Layout of the 1.2 GeV SCL

11. 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

13. C. R&D Activities • Beam Dynamics in the AGS • Injection Painting • Linac Emittance • Transition Crossing • Ring Impedances • Beam Loss and Collimation • AGS Magnet Test • New Power Supply Design • AGS RF Cavity/Ferrite Test • SCL Accelerating Cavity (Join the US SMTF Program) • LLRF for Beam Control • Design of the 1MW Target/Horn System • Target Material Testing (Initiate the US/Japan Collaboration and the BNL LDRD Program)

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

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. Options Layout

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

19. New AGS Main Magnet Power Supply • presently: • Repetition rate 2.5 Hz 1 Hz • Peak power 110 MW 50 MW • Average power 4 MW 4 MW • Peak current 5 kA 5 kA • Peak total voltage  25 kV  10 kV • Number of power converters / feeds 6 2

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

21. AGS RF System Upgrade • Use present cavities with upgraded power supplies • UpgradePresent • Rf voltage/turn 0.8 MV 0.4 MV • RF voltage/gap 20 KV 10 KV • Harmonic number 24 6 (12) • Rf frequency 9 MHz 3 (4.5) MHz • Rf peak power 2 MW 0.75 MW • Rf magnetic field 18 mT 18 mT • 300 kW tetrodes/cavity 2 1

22. Meeting on the SRF Module Test Facility (SMTF)February 23, 2004Argonne National Laboratory Agenda Attendees, 40 people from 10 U.S. Laboratories Chair:  Kwang-Je Kim  Introduction H. Edwards Gaps in Knowledge and Capabilities H. Padamsee

24. TARGET-HORN R&D • MATERIAL STUDIES FOR PULSED HIGH-INTENSITY • PROTON BEAMS • Nicholas Simos, Harold Kirk, • Hans Ludewig, Peter Thieberger, • W-T Weng • BNL • Kirk McDonald, Princeton U • K. Yoshimura, KEK • J. Shepard, SLAC • J. Hylen, FNAL

25. 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.

26. Preliminary Cost Estimate of the BNL - SNBF • Accelerator Systems Total Direct Cost = $156.8 M$

27. Preliminary Cost Estimate – Continued • Total Direct Cost=$156.8 M • Add: ED&I, 15% • Contingency, 30% • BNL Project Overhead, 13% • Total Estimated Cost = $265 M

28. 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. • Such a high power proton driver is essential for very long base line neutrino experiment and also for the neutrino factory.