1. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 JEMMRLA Jefferson Lab Model for Muon RLA Yves Roblin, Kevin Beard, Alex Bogacz, Vasiliy Morosov

2. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Overview Muon RLA acceleration Multi-pass return arcs Scaled Electron Model Preliminary studies Cost estimates Future work

3. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 3 0.9 GeV (  ± ) 0.6 GeV/pass 3.6 GeV Multi-pass Arc Muon RLA (IDS) MAP phone Mtg. January 20, 2012

4. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 60  300  C = 117.6 m Two-pass Arc Layout Simple closing of arc geometry when using similar super cells 1.2 / 2.4 GeV/c arc design used as an illustration can be scaled/optimized for higher energies preserving the factor of 2 momentum ratio of the two passes Vasiliy Morozov Droplet arc: 60  outward bend 300  inward bend 60  outward bend

5. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 ‘Droplet’ Arc - Spreader/Recombiner First few magnets of the super cell have dipole field component only, serving as Spreader/Recombiner * Trajectories are shown to scale B 1.7 Tesla G 28 Tesla/m

6. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Size-down: IDS Muon RLA to JEMMRLA 0.9 GeV (  ± ) 79 m 0.6 GeV/pass linac based on 200 MHz SRF 1.2 GeV 2.4 GeV 1.8 GeV 3.0 GeV 120m 2-pass droplet 120m 2-pass droplet size reduced by factor of 7.5 (1500/200) energies reduced by factor of 206 (m  /m e ) 11 m 16 m 4.5 MeV (e - ) 3 MeV/pass linac based on 1.5 GHz SRF 6 MeV 12 MeV 9 MeV 15 MeV B1.7 Tesla G28 Tesla/m B2.6 Tesla G45 Tesla/m Droplet Arcs: 7 (1+5+1) super-periods × 24 combined function magnets (50 cm ) B975 Gauss G1275 Gauss/cm B638 Gauss G825 Gauss/cm Fits in 25m × 7m

7. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Droplet Arc Architecture (6/12 MeV/c) 7 super-periods (1 out +5 in +1 out) 60  300  C = 16 m super-period C = 2.3 m ‘Integrated’ Magnet: 24 combined function magnets (6.5 cm long, 9.6 cm hor. aperture) separated by 3 cm B~ 650 Gauss G~ 800 Gauss/cm BO01 0 BO02 0 BO03 0.548888 BO04 -0.690966 BO05 0.796576 BO06 -0.627358 BO07 0.596019 BO08 -0.596693 BO09 0.652984 BO10 -0.777233 BO11 0.689622 BO12 -0.523101 G [kGauss/cm] 2  7 

8. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Overall geometry Preliminary for initial proof of concept 2.24 m per cell, each with 24 magnets. Magnet is taken at 6.66 cm long, hard edge Magnet opening in bending plane is 9.6 cm Drift between magnets is 2.66 cm 2 outboard cells, 5 inboard. Total circumference 15.68m

9. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Closed orbit for ideal lattice Closed orbit for 1.2 GeV/c equivalent

10. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Full ring optics at 2.4GeV/c equivalent Current Optics for the return arc

11. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Resteering performance Orbits relative to closed orbit before correction

12. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Resteering performance (cont) Orbits relative to closed orbit after correction

13. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Misalignments and mispowering Studied lattice with following errors: Misalignment Mispowering 25 random machines, corrected with X/Y correctors located after each dipole. BPMs between each dipole, with 20 μm resolution.

14. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Magnet specifications (preliminary) Panofsky type dipole+quad Similar to existing FEL magnet ParameterValueUnits Integrated Gradient0.5T Integrated dipole0.06T.m Aperture width8.6cm Aperture height2.2cm Orbit offset from ctr2.2cm ….

15. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Preliminary magnet modeling Using Radia (ESRF) Ryan Roussel Will use TOSCA for detailed studies and generation of field maps Field is affected by neighboring magnets. Ryan Roussel

16. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Tracking and simulations First estimates were done with simple analytical models. Currently building field maps for subsequent tracking (ELEGANT, G4BEAMLINE, ZGOUBI,..) Magnet design needs to be validated with field map measurements on prototype.

17. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Possible powering scheme (per arc) 12 Voltage driven quad power supplies. One power supply drives 2x7=14 quad coil packages. Choice of optics will identify the tuning quads. These will be equipped with extra current driven power supplies to make them adjustable. 12 power supplies+ 7 shunts to adjust dipole fields on a cell by cell basis.

18. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Costing (very preliminary) ItemQtyUnit costCostNotes Magnets34050001,700,000 Vacuum pumps (ion)16200032,00020 L/S Vacuum pumps (turbo)4500020,000+backing pumps cavities+cryomodule2250,000500,000¼ cryomodule. 1.497Ghz Power supplies485000240,0003KW 1e-4 stab. Shunts14200028,000For dipole adjustment Diagnostics1803000540,000Button bpms+electronics VME, controls10800080,000Crate+CPU Vac. Chambers14180025,2001”x4”, 2.24 m long, curved. Misc (flanges, cables,etc.) N/A100,0001 km of cables.. Vac valves14250035,000 Total cost: about 3.3 M$

19. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Labor TaskFTE’s Girder/vacuum cham. design0.2 Girder Assembly0.3 Girder survey0.2 Girder Alignment0.2 Beamline installation0.3 Diagnostics design0.2 Cabling(routing optimization, making, installing) 0.4 Optics design+tracking+simulations 4 Field mapping0.3 Magnet design1 7 FTE’s

20. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Alternate optics and open issues Considering optics with less combined function magnets. Alternate design with both orbits off center ? Pathlength issues? Higher order multipoles effect on beam shapes? We are just at the beginning.. Need to develop a formal costing scheme to evaluates options (CERN costing tool ?)

21. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Conclusions Electron model of multi-pass arc muon RLA – JEMMRLA (Jlab Electron Model of Muon RLA) Efficient use of RF (4.5 passes) No switchyard - single droplet arc on each side of the linac Demonstration of a new kind of fixed field accelerator Rapid acceleration for future muon facilities (NF/MC) Polarization preservation test (‘Ring’ vs. ‘Figure-8’ topology) Proof of concept for multi-pass arcs based on combined function magnets Possible medical application for gantry design

22. Operated by JSA for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility Y. R. Roblin, NUFACT 2012, July 23-28 2012 Stay clear specifications Beam sigma is about 600 microns. So 30 sigmas is 1.8 cm. Magnet opening is 9.6cm. Orbit spans +/- 2.2 cm, adding 1.8 cm of clearance brings it to 8 cm, well below the 9.6 cm.