Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 1 Muon Acceleration – RLA, FFAG and Fast Ramping Synchrotron NuFact'10, Mumbai, Oct. 21, 2010

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 2 NuFact'10, Mumbai, Oct. 21, 2010 Linac + RLA Moderate re-use of the linac (only a few passes) Switchyard (single bend, horizontal) Individual energy return Arcs for recirculation Increasing number of passes Ramped linac quads Eliminating switchyard Use FFAG-like arcs (two or more passes per arc) Arcs now have larger aperture Matching into linac

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 3 NuFact'10, Mumbai, Oct. 21, 2010 FFAG Rings More passes through RF cavities (10+) – higher efficiency Switchyard in RLAs limits number of passes  instead use single arc with large energy acceptance Linear magnets to get large energy acceptance Linear non-scaling FFAG Challenges Injection and extraction difficult No synchrotron oscillations Amplitude dependent time of flight

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 4 NuFact'10, Mumbai, Oct. 21, 2010 Fast Ramping Synchrotron Allows arbitrary number of passes (high efficiency) Magnets ramped extremely fast Expensive power supplies (Eddy currents) small apertures help to keep power down High average bend field Ramping magnets have low field limit Hybrid lattice with SC magnets

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 5 NuFact'10, Mumbai, Oct. 21, 2010 Ring vs ‘Dogbone’ configurations EE  E/2  E/2  E

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 6 Linac and RLAs  IDS 244 MeV 0.6 GeV/pass 3.6 GeV 0.9 GeV 146 m 79 m 2 GeV/pass 264 m 12.6 GeV IDS Goals: Define beamlines/lattices for all components Matrix based end-to-end simulation (machine acceptance) (OptiM vs ELEGANT) Field map based end-to-end simulation (transmission) GPT vs G4Beamline Error sensitivity analysis Chromaticity compensation NuFact'10, Mumbai, Oct. 21, m RLA with FFAG Arcs ANNEX

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 7 NuFact'10, Mumbai, Oct. 21, 2010 Linear Pre-accelerator – 244 MeV to 909 MeV Transverse acceptance (normalized): (2.5) 2   = 30 mm rad Longitudinal acceptance: (2.5) 2   p  z /m  c  = 150 mm 6 short cryos 15 MV/m 8 medium cryos 17 MV/m 11 long cryos 17 MV/m 1.1 Tesla solenoid 1.4 Tesla solenoid 2.4 Tesla solenoid

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 8 NuFact'10, Mumbai, Oct. 21, 2010 Solenoid Model (Superfish) outer coil inner coil shield ‘Soft-edge’ Solenoid

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 9 NuFact'10, Mumbai, Oct. 21, 2010 Two-cell cavity (201 MHz) – COMSOL Morteza Aslaninejad Cristian Bontoiu J ü rgen Pozimski

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 10 NuFact'10, Mumbai, Oct. 21, 2010 Longitudinal phase-space tracking Initial distribution OptiM ELEGANT  x /  y = 4.8 mm rad  l   p  z /m  c = 24 mm

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 11 NuFact'10, Mumbai, Oct. 21, 2010 Injection/Extraction Chicane 1.5 GeV $Lc = 60 cm $angH =18 deg. $BH = 1.6 Tesla BETA_X&Y[m]DISP_X&Y[m] BETA_XBETA_YDISP_XDISP_Y 2.1 GeV         0.9 GeV 1 m

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz BETA_X&Y[m] DISP_X&Y[m] BETA_XBETA_YDISP_XDISP_Y NuFact'10, Mumbai, Oct. 21, 2010 Multi-pass Linac Optics – Bisected Linac 1-pass, MeV ‘half pass’, MeV initial phase adv/cell 90 deg. scaling quads with energy mirror symmetric quads in the linac quad gradient

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz cells in 2 cells out (  out =  in and  out = -  in, matched to the linacs) transition E =1.2 GeV NuFact'10, Mumbai, Oct. 21, 2010 Mirror-symmetric ‘Droplet’ Arc – Optics

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 14 NuFact'10, Mumbai, Oct. 21, 2010 beamlineRF cavitiessolenoidsdipolesquadssext 1-cell2-cell pre-accelerator66225 inj-chic I RLA I linac2426 arc13543 arc arc arc inj-chic II RLA II linac8042 arc13543 arc arc arc Lambertson1 Component count

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 15 RLA with Two-Pass FFAG Arcs NuFact'10, Mumbai, Oct. 21, 2010   41 m

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz GeV/c Linear Optics of Arc 1 Unit Cell NuFact'10, Mumbai, Oct. 21, 2010 Combined-function bending magnets are used 1.2 GeV/c orbit goes through magnet centers Linear optics controlled by quadrupole gradients in symmetric 3-magnet cell Dispersion compensated in each 3-magnet cell 3-magnet cell Vasiliy Morozov MAD-X (PTC)

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 17 sextupole and octupole components 2.4 GeV/c Linear Optics of Arc 1 Unit Cell NuFact'10, Mumbai, Oct. 21, 2010 Unit cell composed symmetrically of three 3-magnet cells Off-center periodic orbit Orbit offset and dispersion are compensated by symmetrically introducing sextupole and octupole field components in the center magnets of 3-magnet cells symmetric unit cell MAD-X (PTC)

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 18 Cell Matching NuFact'10, Mumbai, Oct. 21, GeV/c2.4 GeV/c outward inwardoutward inward

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 19 Matching of Linac Optics to Arcs NuFact'10, Mumbai, Oct. 21, 2010 Adjust linac quads to match arc optics at 1.2, 1.8, 2.4, and 3.0 GeV/c 1 st half pass through linac 0.9 GeV/c 1.2 GeV/c, matched to 1.2 GeV/c optics of arc 1 1 st full pass through linac 1.2 GeV/c 1.8 GeV/c, matched to 1.8 GeV/c optics of arc 2 2 nd full pass through linac 1.8 GeV/c 2.4 GeV/c, matched to 2.4 GeV/c optics of arc 1 Matching to 3.0 GeV/c optics of arc 2 after 3 rd full pass through the linac is in progress

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 20 NuFact'10, Mumbai, Oct. 21, 2010 NS-FFAG IDS (12-25 GeV) Many passes (11) - no switchyard Injection/extraction challenging 15 cm radius, 0.1 T field, 7 needed Ring Optics - triplet lattice with long drifts Longer drifts ease injection/extraction Double cavity in long drift: better gradient Reduce longitudinal distortion: large transverse amplitude Scott Berg

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 21 NuFact'10, Mumbai, Oct. 21, 2010 Main Ring Lattice Identical FDF triplets Superconducting combined-function magnets 5 m drifts to accommodate septum One two-cell MHz SCRF cavity in most drifts Scott Berg

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 22 NuFact'10, Mumbai, Oct. 21, 2010 Main Ring Lattice Cells 64 Circumference (m) 667 Long drift (m) 5.0 Cavities 48 RF Voltage (MV) 1214 Turns 11.6 D F. Max field (T) Magnet radius (mm) Scott Berg

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 23 NuFact'10, Mumbai, Oct. 21, 2010 Main Ring Magnets Superconducting combined-function Separate dipole and quadrupole layers Imperial College

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 24 NuFact'10, Mumbai, Oct. 21, 2010 RF Cavities Use the Study II 30 mm aperture design Two-cell SCRF cavities 25.5 MV maximum energy gain per cavity 1 MW input power 3 ms fill time Scott Berg

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 25 NuFact'10, Mumbai, Oct. 21, 2010 Injection/Extraction Injection/extraction on opposite sides of ring Horizontal plane: inside injection, outside extraction Mirror-symmetric to handle both signs Two septa with kickers between Maximum 0.1 T kicker fields (Rise/fall times < 2 µs) Maximum 2 T septum fields Increased magnet apertures needed Jaroslaw Pasternak

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 26 NuFact'10, Mumbai, Oct. 21, 2010 Septa Magnets Jaroslaw Pasternak

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 27 NuFact'10, Mumbai, Oct. 21, 2010 Chromaticity Correction Nonlinear coupling of transverse into longitudinal Occurs everywhere, most noticeable in non-scaling FFAG Correct chromaticity to reduce some negative impacts on performance/cost Treat as potential performance improvement Scott Berg

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 28 NuFact'10, Mumbai, Oct. 21, 2010 SC magnets fixed field + warm magnets ramped Beam not centered in magnets Maintain beam synchronization with RF Optimization paths: Vary quad and ramp dipole fields Keep time of flight and tunes fixed Minimize horizontal position variation Don Summers Fast Ramping Synchrotron

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 29 NuFact'10, Mumbai, Oct. 21, 2010 Hybrid Magnets

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 30 NuFact'10, Mumbai, Oct. 21, 2010 Don Summers Fast Ramping Synchrotron

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 31 NuFact'10, Mumbai, Oct. 21, 2010 Magnet Laminations Don Summers

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 32 NuFact'10, Mumbai, Oct. 21, 2010 Iron magnets behind ceramic vacuum chambers Similar to a kicker Kickers have large highly resistive low-frequency impedance Normally a significant contribution to impedance We are proposing to make an entire ring out of them... Ring Impedance

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 33 NuFact'10, Mumbai, Oct. 21, 2010 Different acceleration schemes appropriate in various energy ranges Opportunities and Challenges R&D required RLAs are rather straightforward, but: Limitted to a few turns – modest efficiency Non-scaling FFAGs will get more turns, but: Small transverse emittance eliminates main challenge Lack synchrotron oscillations RLA with FFAG arcs: Transporting two or more discrete energies through the same beam line Proof-of principle solution – two NS-FFAG arcs matched to the linac Summary

Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Alex Bogacz 34 NuFact'10, Mumbai, Oct. 21, 2010 Fast Ramping Synchrotrons Good hardware and power efficiency Strong synchrotron oscillations Challenges to face Proof-of principle demonstration of the fast ramped magnets? Does ramped magnet system cost outweigh the benefit? Is the magnet impedance unmanageably large? Summary – cont.