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Fermilab, Proton Driver, Muon Beams, Recycler. David Neuffer Fermilab NufACT05. Proton Driver and Muon beams. 8GeV Linac can produce streams of 1.5 ×10 14 8GeV protons at 10Hz > 10 22 protons/year Only 1/15 of these needed for Main Injector
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Fermilab, Proton Driver, Muon Beams, Recycler David Neuffer Fermilab NufACT05
Proton Driver and Muon beams • 8GeV Linac can produce streams of 1.5×1014 8GeV protons at 10Hz • > 1022 protons/year • Only 1/15 of these needed for Main Injector • Are there muon beam experiments that could use this intensity ?? • Tertiary muon beams: • P + X → π • π → μ + ν • 10-2 μ/p → 1020 μ/year or more
LFV: m-A e-A can use high intensity Desirable Beam Characteristics But bunched beam is needed
m-A e-A experiments • Next generation of m-A e-A experiments has been proposed • MECO – based at BNL • PRISM-PRIME – based at KEK/JHF • Neither experiment is fully funded • Could either (or both) be hosted at FNAL proton driver ? m-A e-A produces monoenergetic e- (~105MeV)
10 -11 10 -13 10 -15 10 -17 10 -19 10 -21 Past and future LFV limits SUSY predictions ofm-A e-A 10 –5 MECO single event sensitivity PRIME single event sensitivity 10 -11 10 -13 100 300 100 300 GeV From Barbieri, Hall, Hisano …
MECO layout Superconducting Detector Solenoid (2.0 T – 1.0 T) Tracker Muon Stopping Target Superconducting Transport Solenoid (2.5 T – 2.1 T) Muon Beam Stop Crystal Calorimeter Superconducting Production Solenoid (5.0 T – 2.5 T) Collimators Time structure
PRISM-PRIME (Y. Kuno et al.) • High intensity pulsed proton beam (bunch length <10ns) • 100-1000Hz bunches • Pion capture solenoid & decay • Phase rotation with rf field • Δp/p : ±30% 3% • Similar to the front end of the neutrino factory
Proton Beam requirements • MECO experiment • Requires pulses of ~8 GeV protons (<30ns long) every ~1μs (1.4μs) • Obtained by slow extraction of short bunches (in AGS) • Design requires 41013 p/s, 1.5 10-3 captured μ’s/proton • ~61017μ/year from ~4 1020 p/year • PRISM-PRIME experiment • Requires proton pulses (<10ns long) at 103/s (~1ms) • 4 1014 p/s (50GeV) 10-2 to 10-3μ’s/proton • Up to 1022 p/year, > 1019 μ/year • Single-turn extraction of short bunches (<10ns) • Both require pulsed beams, proton linac beam must be repackaged in an accumulator ring
Recycler as accumulator ring ? • 8GeV Linac produces 1ms pulses at 10 Hz • H- injection into Recycler • 1ms fills circumference • (100 turns) • Bunch beam into pattern required for expt. • Harmonic 10 buncher for MECO, slow extraction • Harmonic 100 buncher for PRIME, single bunch extraction But: Recycler circumference is large 100ms may be too short a time for bunching
Space Charge Difficulty • Space Charge tune shift: • Parameters: Ntot=1.51014,εN =20π mm-mrad • MECO: 30ns/1μs : BF= 0.03 →δν = 4 : too large • Reduce N to 1.51013 →δν = 0.4 • Reduce N to 0.41013 →δν = 0.1 • PRISM/PRIME 10ns bunches, 100/ring • BF= 0.1 →δν =1.2: too large (but closer) • Larger εN, smaller Ntot, • Smaller circumference ring would be better
Recycler – Bunching (~for PRISM) • Harmonic 100 buncher (9MHz) • Bunch for 0.1s • (Vrf ramps to 140kV) • Bunch lengths reduced to ~5ns rms (Prism wants < 10ns full width.) • Could then extract bunches one at a time over ~0.1s • Uses 1/2 the possible linac pulses (500 bunches/s for PRISM) (100 at 5Hz)
Recycler – Bunching for ~MECO • Harmonic 10 buncher (0.9MHz) • Barrierbucket rf • Bunch for ~1s • (Vrf ramps to ~30kV) • Bunch lengths reduced to ~50ns rms (MECO wants ~30ns full width.) • Could then extract bunches in slow extraction over ~1s
Other potential proton storage schemes • Accumulator or Debuncher (C= ~454m) after 2010… • Large aperture machines • Difficult to inject H- (must bend beam from Linac) (B < 0.05T, ρ > ~600m) • Could take debunched protons from Recycler or Main Injector(in ~450m chunks) • Or Old linac + Booster • Bunch into pattern needed for experiments • Bunching easier than Recycler • Better match for MECO
Generic High intensity muon beam • Detailed m source design does not exist • Straw man design worked out for the front end of a n factory • supported by MARS simulations (Ray et al.) • Target + capture solenoid + drift (forward capture) • 1.4 x 1022 protons/year at 8 GeV yields ~3 x 1021 muons/year. Charged particle spectra at end of decay channel
References • W. Foster et al., Proton Driver http://tdserver1.fnal.gov/project/8GeVLinac/DesignStudy/ • W. Molson, “The MECO Experiment to Search for -Ne-N with 10-17 Sensitivity”, U. Va. Seminar, June 2004 • MECO • ‘RSVP’ Rare Symmetry Violating Processes (MECO-KOPIO) NSF proposal, October 1999. • PRISM Working group • “An Experimental Search for the μ−−e− Conversion Process at an Ultimate Sensitivity of the Order of 10−18with PRISM”, The Prime Working Group, Jan. 1, 2003. • R. Ray & D. Roberts, Proton Driver physics study
Summary • Muon Beams from the Proton Driver could be very useful • Potential muon beam facilities could be developed: • MECO, PRISM … could be hosted • More Detailed design needed • Proton Collection • Recycler, Accumulator, Debuncher, … • New Stretcher/Buncher ring ?? • Beam line(s) • Experimental area(s)
Proton Driver Parameters 8 GeV LINAC Energy GeV 8 Particle Type H- Ions, Protons, or Electrons Rep. Rate Hz 10 Active Length m 671 Beam Current mA 25 Pulse Length msec 1 Beam Intensity P / pulse 1.5E+14 (can also be H-, P, or e-) P/s 1.5E+15 Linac Beam Power MW avg. 2 MW peak 200 MAIN INJECTOR WITH 8 GeV LINAC MI Beam Energy GeV 120 MI Beam Power MW 2.0 MI Cycle Time sec 1.5 filling time = 1msec MI Protons/cycle 1.5E+14 5x design MI Protons/hr P / hr 3.6E+17 H-minus Injection turns 90 MI Beam Current mA 2250