Target Considerations for Nufact and Superbeams

1. Target Considerations for Nufact and Superbeams ISS Meeting RAL April 26, 2006

2. Main Study Parameter • Design for: • 4 MW

3. Driving Target Issues • Meson Production • Proton Beam Pulse Length • Proton Beam Structure

4. Stephen Brook’s Analysis Pions • Pions counted at rod surface • B-field ignored within rod (negligible effect) • Proton beam assumed parallel • Circular parabolic distribution, rod radius Protons 1cm Solid Tantalum 20cm

5. Yield of p± and K± in MARS Finer sampling • No surprises in SPL region • Statistical errors small • 1 kaon  1.06 muons

6. The Study 2 Capture Concept • Maximize Pion/Muon Production • Soft-pion Production • High Z materials • High Magnetic Field Solenoid

7. The Study2 Target System • Consider Liquid Hg • Count all the pions and muons that cross the transverse plane at z=50m. • For this analysis we select all pions and muons with KE< 0.35 GeV.

8. Optimize Soft-pion Production using Hg

9. Meson KE < 350 MeV at 50m Mesons/Proton Mesons/Proton normalized to beam power

10. Process mesons through Cooling Consider mesons within acceptance of ε┴ = 30π mm and εL = 150π mm after cooling 350 MeV Use meson count with KE < 350 MeV as a figure of merit.

11. Post-cooling 30π Acceptance

12. Carbon Target Parameters Search

13. Carbon Target Optimization Set R=1.25cm; tilt angle = 50 mrad; Length=60cm; Z=-40cm

14. Proton KE Scan with Carbon • Count mesons within acceptance of • ε┴ = 30π mm and • εL = 150π mm • after cooling

15. Summary of Results • Compare Meson production for Hg at 24 GeV and 10 GeV • Compare Meson production for C at 24 GeV and 5 GeV • Compare Meson production for Hg at 10 GeV and C at 5 GeV 1.07 1.10 1.90 1.77 1.18 1.22

16. Conclusion • Optimum Input Proton Beam Energy for Study2a configuration with Hg: • 8 to 20 GeV • Superbeam proton beams energies: • Mini-boone 8GeV • BNL AGS 28 GeV • Jpark 30 to 50 GeV • Numi 60 to 120 GeV • CNGS 400 GeV

17. Driving Target Issues • Meson Production • Proton Beam Pulse Length • Proton Beam Structure

18. Proton Beam Pulse Length Study 2a J. Gallardo, H. Kirk

19. Conclusion • Optimum Proton Beam Pulse Length for Study2a configuration: • 1ns • Superbeam proton beams energies: • BNL AGS 28 GeV 10ns • Numi 4 μs • CNGS 2 x 5 μs

20. Driving Target Issues • Meson Production • Proton Beam Pulse Length • Proton Beam Structure

21. Proton Beam Intensity Protons per pulse required for4MW

22. Shock Stress Analysis N. Simos

23. SUMMARY of Performance Solid Targets

24. 5 X 50 Proton Beam Structure • Johnstone, Meot, Rees • 10 GeV Proton Beam • 50 Hz • n = 5 sub-structure => 10 x 1012 protons (10TP) per micro-bunch • Accelerate 3 to 10 GeV with harmonic 36 structure and frequency of 13.079-13.417 MHz • Adiabatically compress to 2ns • Further compress to 1ns with f=80.5 MHz and f=201.25MHz

25. Pulse Delivery to Target • ΔT = 13 μs => 52 μs bunch structure • Liquid Target • ΔT = 65 μs => 260 μs bunch structure • Solid Target

26. Muon Bunch Pattern in Decay Rings • . > 100ns intervals 80 μ+ 127(130) 148(133) solid/liquid 80 μ+ 127(130) 2 of 5 interleaved 80 μˉ bunchtrains of 2nd ring 80 μ+ 80 μ+ 127(!30) 80 μ+ 127(130) 80 full and 127 (or 130) empty RF buckets