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μ- Capture, Energy Rotation, Cooling and High-pressure Cavities. David Neuffer Fermilab. 0utline. Motivation Study 2AP Neutrino factory … Muon Collider, … “High-frequency” Buncher and Rotation Study 2Ap scenario, obtains up to ~0.2 /p Integrate cooling into phase-energy rotation
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μ-Capture, Energy Rotation, Cooling and High-pressure Cavities David Neuffer Fermilab
0utline • Motivation • Study 2AP Neutrino factory … • Muon Collider, … • “High-frequency” Buncher and Rotation • Study 2Ap scenario, obtains up to ~0.2 /p • Integrate cooling into phase-energy rotation • Gas-Cavity Variations • Cooling in bunching and phase rotation • Higher gradient, lower frequency ??? • Shorter system, fewer bunches • Optimization …. • Polarization • Use high gradient rf near target to improve polarization
Advantages of high-pressure cavities • high gradient rf • In magnetic fields B=1.75T, or more … • With beam • Change cavity frf by • Can Integrate cooling with capture • Capture and phase-energy rotation + cooling • Can get high-gradient at low frequencies (30, 50, 100 MHz ???) • Beam manipulations • Polarization Research can be funded…
Study2A Dec. 2003June2004 • Drift –110.7m • Bunch -51m • V’ = 3(z/LB) + 3 (z/LB)2 MV/m (× 2/3) (85MV total) • (1/) =0.0079 • -E Rotate – 52m – (416MV total) • 12 MV/m (×2/3) • P1=280 , P2=154V = 18.032 • Match and cool (100m) • V’ = 15 MV/m (× 2/3) • P0 =214 MeV/c • 0.75 m cells, 0.02m LiH
Study2AP June 2004 scenario • Drift –110.7m • Bunch -51m • V(1/) =0.0079 • 12 rf freq., 110MV • 330 MHz 230MHz • -E Rotate – 54m –(416MV total) • 15 rf freq. 230 202 MHz • P1=280 , P2=154NV = 18.032 • Match and cool (80m) • 0.75 m cells, 0.02m LiH • “Realistic” fields, components • Fields from coils • Be windows included
Simplest Modification • Add gas + higher gradient to obtain cooling within rotator • ~300MeV energy loss in cooling region • Rotator is 51m; • Need ~6MeV/m H2 Energy loss • 9MeV/m if cavities occupy 2/3 • ~30% Liquid H2 density • Alternating Solenoid lattice in rotator • 21MV/m rf • Try shorter system … Cool here
Short bunch train option • Drift (20m), Bunch–20m (100 MV) • Vrf = 0 to 15 MV/m ( 2/3) • P1 at 205.037, P2=130.94 • N = 5.0 • Rotate – 20m (200MV) • N = 5.05 • Vrf = 15 MV/m ( 2/3) • Palmer Cooler up to 100m • Match into ring cooler • ICOOL results • 0.12 /p within 0.3 cm • Could match into ring cooler (C~40m) (~20m train) 40m 60m 95m
FFAG-influenced variation – 100MHz • 100 MHz example • 90m drift; 60m buncher, 40m rf rotation • Capture centered at 250 MeV • Higher energy capture means shorter bunch train • Beam at 250MeV ± 200MeV accepted into 100 MHz buncher • Bunch widths < ±100 MeV • Uses ~ 400MV of rf
Lattice Variations (50Mhz example) Example I (250 MeV) • Uses ~90m drift + 100m 10050 MHz rf (<4MV/m) ~300MV total • Captures 250200 MeV’s into 250 MeV bunches with ±80 MeV widths Example II (125 MeV) • Uses ~60m drift + 90m 10050 MHz rf (<3MV/m) ~180MV total • Captures 125100 MeV’s into 125 MeV bunches with ±40 MeV widths
Polarization for μ+-μ- Colliders • Start with short proton bunch on target < ~1ns • Before π⇒μ+ν decay, use low-frequency rf to make beam more monochromatic • ~50MV in ~5m? • Drift to decay (~10m?) • Higher energy μ’s pol. + • Lower energy μ’s pol. – • ¼ Phase-Energy rotation • ~10m • Rebunch at ~2× frequency • +’s in one bunch • -’s in other bunch + - + -
Summary • High-frequency Buncher and E Rotator (ν-Factory) improved (?) with high-pressure cavities • Shorter systems • Lower Frequency (fewer bunches). • μ+-μ- Colliders … • Polarization … To do: • Optimizations, Best Scenario, cost/performance …
Current Status (New Scientist) (or μ+-μ- Collider)