TeV Scale Muon RLA Complex Large Emittance MC Scenario

Transcription

1 TeV Scale Muon RLA Complex Large Emittance MC Scenario Alex Bogacz and Kevin Beard Muon Collider Design Workshop, BNL, December 1-3, 29

2 Outline Large Emittance MC Neuffer s Collider Acceleration Scheme with three Dogbone RLAs Linac + RLA I: RLA II: RLA III:.3-4 GeV 4.5-pass (2 MHz SRF) 4-52 GeV 12-pass (4 MHz SRF) 52-1 GeV 12-pass (8 MHz SRF) Muon RLA Beam dynamics choices Fesibility/Cost considerations Muon Collider Design Workshop, BNL, December 1-3, 29

3 Muon RLA Beam dynamics choices Dogbone (Single Linac) RLA better orbit separation at the linac ends Longitudinal Compression via synchrotron motion Bisected linac Optics mirror symmetric quad gradient along the linac Pulsed linac Optics. even larger number of passes is possible if the quadrupole focusing can be increased as the beam energy increases (proposed by Rol Johnson) Flexible Momentum Compaction return arc Optics to accommodate two passes (two neighboring energies) NS-FFAG like Optics (proposed by Dejan Trbojevic) Pulsed arcs? ramping arc magnets to further reuse the arcs Muon Collider Design Workshop, BNL, December 1-3, 29

4 How to get s from 3 GeV to 2 TeV before they all decay away? average gradient over whole path determines survivability e - t (E f /E i ) - m o /gc TELSA cavities ~ real estate g ~ 31 MeV/m 64.4 km linac 97% survival g ~$4,M * *@Jlab ~ $2M/GeV Muon Collider Design Workshop, BNL, December 1-3, 29

5 Large Emittance MC Scenario Proton Linac 8 GeV Accumulator, Buncher Hg target Drift, Bunch, Cool 2m Dave Neuffer Linac RLAs Detector Parameter Symbol Value Proton Beam Power P p 2.4 MW Bunch frequency F p 6 Hz Protons per bunch N p Proton beam energy E p 8 GeV Number of muon bunches n B 12 +/- / bunch N 1 11 Transverse emittance t,n.3m Collision * *.5m Collision max * 1m Beam size at collision x,y.13cm Beam size (arcs)( * =1m) x,y.55cm Beam size IR quad max 5.4cm Collision Beam Energy E +,E _ 1 TeV (2TeV total) Storage turns N t 1 Luminosity L L=f n s n b N 2 /4 2 Collider Ring Muon Collider Design Workshop, BNL, December 1-3, 29

6 Bunch train for Large Emittance MC Drift, buncher, rotator to get short bunch train (n B = 1): 217m 125m 57m drift, 31m buncher, 36m rotator Rf voltages up to 15MV/m ( 2/3) Obtains ~.1 μ/p 8 in ref. acceptance A t <.3, A L <.2 Choose best 12 bunches ~.8 μ/p 8 per bunch ~.5 μ/p 8 in acceptance protons μ/bunch in acceptance ε t,rms, normalized.3m (accepted μ s) ε L,rms, normalized.34m (accepted μ s) Dave Neuffer Muon Collider Design Workshop, BNL, December 1-3, 29

7 Large Emittance MC Front End Muon Collider Design Workshop, BNL, December 1-3, 29

8 Large Emittance MC Front End Muon Collider Design Workshop, BNL, December 1-3, 29

9 Size_X[cm] Size_Y[cm] 3 3 Pre-accelerator Longitudinal dynamics Wed Jan 16 23:24:25 28 OptiM - MAIN: - D:\4GeV_RLA\PreLinac\Linac_sol.opt Transverse acceptance (normalized): (2.5) 2 Longitudinal acceptance: (2.5) 2 p z/m c = 2 mm = 25 mm rad Ax_bet Ay_bet Ax_disp Ay_disp short cryos 12 MV/m 8 medium cryos 12 MV/m 16 long cryos 12 MV/m 1.1 Tesla solenoid 1.2 Tesla solenoid 2.4 Tesla solenoid Muon Collider Design Workshop, BNL, December 1-3, 29

10 Energy [GeV] Dp/p RF phase [deg] Synchrotron phase/2 PI Longitudinal matching Synchrotron motion Longitudinal acceptance: p/p=.17 or = 93 (2MHz) s[m] s [m] s [m] 1 1 Phase [deg] 1 Muon Collider Design Workshop, BNL, December 1-3, 29

11 4 GeV RLA Longitudinal compression Muon Collider Design Workshop, BNL, December 1-3, 29

12 4 GeV RLA Accelerator Performance Muon Collider Design Workshop, BNL, December 1-3, 29

13 Size_X[cm] Size_Y[cm] DISP_X& Y[m] 3 5 Beam envelopes end of RLA II (5 GeV) Wed Dec 2 23::29 29 OptiM - MAIN: - C:\Working\Dogbone_pulsed\pulsed\Linac12.opt BETA_X BETA_Y DISP_X DISP_Y 5 Pass 12 Wed Dec 2 23:4:31 29 OptiM - MAIN: - C:\Working\Dogbone_pulsed\pulsed\Linac12.opt Transverse acceptance (normalized): (2.5) 2 = 25 mm rad Ax_bet Ay_bet Ax_disp Ay_disp 5 Muon Collider Design Workshop, BNL, December 1-3, 29

14 A few thoughts on scaling for dipoles, the stored energy ~ power ~ cost 2 B 2 for quadrupoles, stored energy ~ power ~ cost 4 G 2 Muon Collider Design Workshop, BNL, December 1-3, 29

15 Hybrid magnets 3.T is the best we can do ±1.8T 8.8T ±1.8T Ln/2 Ls Ln/2 Don Summers P max /P min = B max /B min = (Bs Ls + Bn Ln) (Bs Ls - Bn Ln) x (P max /P min -1)/(P max /P min +1) B avg = f (x+1)/(x/bn+1/bs) B avg [T] P max /P min, B avg 3.T P max /P min, Bs B avg 2 Bn P max /P min Muon Collider Design Workshop, BNL, December 1-3, 29

16 Large Emittance MC vs LEMC.rough numbers for normal 1.8T magnets LEMC emittance (153 GeV, 2 m) N 2.1 mm-mrad 1 5 mm 9mm small aperture little stored energy ~ 37 J/m 11.5kJ/m power ~ 22 kw/m 7 MW/m Muon Collider Design Workshop, BNL, December 1-3, 29

17 Large Emittance MC Conclusions ramped dipole magnets mean large arcs low emittance makes for small apertures little stored energy, power, costs most schemes require fast pulsed magnets of some kind Muon Collider Design Workshop, BNL, December 1-3, 29

18 DISP_X&Y[m] 3 5 DISP_ X& Y[m] 3 5 Multi-pass bisected linac Optics half pass, 4-6 GeV Tue Jun 9 15:34:4 29 OptiM - MAIN: - C:\Working\double_dogbone\Dogbone_FODO\baseline\Linac5.opt initial phase adv/cell 9 deg. scaling quads with energy quad gradient BETA_X BETA_Y DISP_X DISP_Y pass, 6-1 GeV mirror symmetric quads in the linac Fri Jan 23 15:39:23 29 OptiM - MAIN: - N:\bogacz\RLA explore\dogbone_fodo\baseline\lattice with space in the quad gradient BETA_X BETA_Y DISP_X DISP_Y Muon Collider Design Workshop, BNL, December 1-3, 29

19 DISP_X& Y[m] 12 5 DISP_X&Y[m] 1 5 Multi-pass linac Optics 4-pass, GeV Fri Apr 3 5:33:33 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with space in quad gradient BETA_X BETA_Y DISP_X DISP_Y pass, 3-34 GeV Fri Apr 3 5:27:33 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with space in the quad gradient BETA_X BETA_Y DISP_X DISP_Y Muon Collider Design Workshop, BNL, December 1-3, 29

20 -3 DISP_X& DISP_X& Y[ m] Linac-to-Arc Beta Match E =5 GeV Fri Jan 23 15:2:37 29 OptiM - MAIN: - N:\bogacz\IDS\Linacs_bisect\Linac5.opt Wed Jun 11 11:53:6 28 OptiM - MAIN: - D:\IDS\Arcs\Arc1.opt BETA_X BETA_Y DISP_X DISP_Y BETA_X BETA_Y DISP_X DISP_Y 72 Matched by design 9 phase adv/cell maintained across the junction No chromatic corrections needed Muon Collider Design Workshop, BNL, December 1-3, 29

21 -3 dp/p * 1, -3 dp/p * 1, B ETA_X&Y[m] D ISP_X& Y[m] 15 3 Mirror-symmetric Droplet Arc Optics Tue Jun 1 21:14:41 28 OptiM - MAIN: - D:\IDS\Arcs\Arc1.opt E =5 GeV ( out = in and out = - in, matched to the linacs) BETA_X BETA_Y DISP_X DISP_Y 13 2 cells out transition 2 cells out 1 cells in transition footprint x [cm] S [cm] View at the lattice end 4-5 z [cm] -4 S [cm] View at the lattice beginning 4 Muon Collider Design Workshop, BNL, December 1-3, 29

22 Pulsed linac Dogbone RLA (8-pass) 4 GeV 4 GeV/pass 34 GeV Quad pulse would assume 5 Hz cycle ramp with the top pole field of 1 Tesla. Equivalent to: maximum quad gradient of G max =2 kgauss/cm (5 cm bore radius) ramped over = 1-3 sec from the initial gradient of G =.1 kgauss/cm (required by 9 phase advance/cell FODO structure at 3 GeV). G 8 =13 G = 1.3 kgauss/cm These parameters are based on similar applications for ramping corrector magnets such as the new ones for the Fermilab Booster Synchrotron that have 1 khz capability T 8 sec = 1 1 sec -8 T 1-2 Muon Collider Design Workshop, BNL, December 1-3, 29

23 1 1 Fixed vs Pulsed linac Optics (8-pass) 5 DISP_X& Y[m] 5 DISP_X&Y[m] Fri Apr 3 5:31:8 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with space Fixed BETA_X BETA_Y DISP_X DISP_Y Fri Apr 3 5:33:33 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with space in th Pulsed BETA_X BETA_Y DISP_X DISP_Y Muon Collider Design Workshop, BNL, December 1-3, 29

24 12 12 Fixed vs Pulsed linac Optics (12-pass) 5 DISP_X& Y[m] 5 DISP_X&Y[m] Fri Apr 3 5:57:32 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with spa Fixed BETA_X BETA_Y DISP_X DISP_Y Fri Apr 3 5:27:33 29 OptiM - MAIN: - D:\RLA explore\dogbone_fodo\baseline\lattice with space in the mi Pulsed BETA_X BETA_Y DISP_X DISP_Y Muon Collider Design Workshop, BNL, December 1-3, 29

25 Multi-pass Arc besed on NS-FFAG Dejan Trbojevic, 1. Large energy acceptance 2. Very small orbit offsets 3. Reduce number of arcs 4. Very compact structure FMC Optics (NS-FFAG-line) Compact triplet cells based on opposed bend combined function magnets B B Gx B x y Gy Muon Collider Design Workshop, BNL, December 1-3, 29

26 DISP_X& Y[m] DISP_X& Y[m] Flexible Momentum Compaction Cells Guimei Wang Wed Nov 19 1::59 28 OptiM - MAIN: - D:\SBIR\FMC\Optics\ex4_inv.opt Wed Nov 19 9:59:58 28 OptiM - MAIN: - D:\SBIR\FMC\Optics\ex4.opt, BETA_X BETA_Y DISP_X DISP_Y BETA_X BETA_Y DISP_X DISP_Y Mag. L(cm) B(kG) G(kG/cm) θ ( deg) D(cm) BD <D<.23 BF <D<.72 BDre <D< BFre <D<-.6 Strong focusing (middle magnet) yields very small beta functions and dispersion Momentum offset of 6% corresponds to the orbit displacement of about 4.3 cm. Muon Collider Design Workshop, BNL, December 1-3, 29

27 x[ cm] DISP_ X& Y[m] DISP_ X& Y[m] NS-FFAG multi-pass Droplet Arc Wed Nov 19 1:11:56 28 OptiM - MAIN: - D:\SBIR\FMC\Optics\multi cell.opt Wed Nov 19 1:13:45 28 OptiM - MAIN: - D:\SBIR\FMC\Optics\multi cell.opt, BETA_X BETA_Y DISP_X DISP_Y BETA_X BETA_Y DISP_X DISP_Y outward 3 inward 6 outward z[ cm] MADX-PT Polymorphic Tracking Code is used to study multi-pass beam dynamics for different pass beams: path length difference, optics mismatch between linac and arcs, orbit offset and tune change is being studied. Muon Collider Design Workshop, BNL, December 1-3, 29

28 Beta functions vs. Energy Inward bending cell Outward bending cell For different energy spread, ~the same beta function in opposite bending cell. With MADX- Polymorphic Tracking Code. Energy spread changes from -3% to 9% Muon Collider Design Workshop, BNL, December 1-3, 29

29 Summary Large Emittance MC Linac + RLA I: RLA II: RLA III: Acceleration Scheme with three Dogbone RLAs.3-4 GeV 4.5-pass (2 MHz SRF) 4-52 GeV 12-pass (4 MHz SRF) still large tr. beam size 52-1 GeV 12-pass (8 MHz SRF) serious problems with big magnets FODO bisected linac Optics large number of passes supported (8 passes) Pulsed linac Optics further increase from 8 to 12-pass Flexible Momentum Compaction (FMC) return arc Optics allows to accommodate two passes (two neighboring energies) Muon Collider Design Workshop, BNL, December 1-3, 29