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Status and Plans for Linac and RLAs. Alex Bogacz. Acceleration Scheme – IDS Goals. Engineering design foundation Define beamlines/lattices for all components Design lattices for transfer lines between the components
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Status and Plans forLinac and RLAs Alex Bogacz
Acceleration Scheme – IDS Goals • Engineering design foundation • Define beamlines/lattices for all components • Design lattices for transfer lines between the components • Resolve physical interferences, beamline crossings etc Floor Coordinates • Carry out end-to-end tracking study Machine Acceptance • Engineer individual active elements (magnets and RF cryo modules) EUROnu Annual Meeting, CERN, March 26, 2009
0.9 GeV 244 MeV 146 m 79 m 0.6 GeV/pass 3.6 GeV 264 m 12.6 GeV 2 GeV/pass Towards Engineering Design Foundation EUROnu Annual Meeting, CERN, March 26, 2009
‘Dogbone’ RLA – Opportunities and Challenges • RLA requirements • Large transverse and longitudinal acceptances • Simultaneous acceleration of both m+m- species • Rapid acceleration – fixed field magnets, high gradient SRF • Manageable orbit separation at recirculation arcs • Beam dynamics issues • ‘Full bucket’ acceleration – longitudinal compression • Phase slippage in the linacs • Multi-pass linac optics • Droplet return arc – compact lattice design and matching • Chromatic corrections
Linear Pre-accelerator – 244 MeV to 909 MeV Transverse acceptance (normalized): (2.5)2eN = 30 mm rad Longitudinal acceptance: (2.5)2 sDpsz/mmc= 150 mm 8 medium cryos 17 MV/m 6 short cryos 15 MV/m 11 long cryos 17 MV/m 2.4 Tesla solenoid 1.4 Tesla solenoid 1.1 Tesla solenoid EUROnu Annual Meeting, CERN, March 26, 2009
Longitudinal phase-space (s, Dp/p) axis range: s = ±25 cm, Dp/p = ±0.2 Linear Pre-accelerator – 244 MeV to 909 MeV Transverse acceptance (normalized): (2.5)2eN = 30 mm rad Longitudinal acceptance: (2.5)2 sDpsz/mmc= 150 mm EUROnu Annual Meeting, CERN, March 26, 2009
m- m- m+ m+ Injection double-chicane m+ m- EUROnu Annual Meeting, CERN, March 26, 2009
Pre-accelerator–Chicane–Linac Matching a = 2×10-5 EUROnu Annual Meeting, CERN, March 26, 2009 NFMCC Collaboration Meeting, LBNL, January 27, 2009
Multi-pass linac Optics ‘half pass’ , 900-1200 MeV initial phase adv/cell 90 deg. scaling quads with energy quad gradient 1-pass, 1200-1800 MeV mirror symmetric quads in the linac quad gradient EUROnu Annual Meeting, CERN, March 26, 2009
Multi-pass linac Optics 2-pass, 1800-2400 MeV phase adv. diminish uniformly in both planes 3-pass, 2400-3000 MeV EUROnu Annual Meeting, CERN, March 26, 2009
Multi-pass linac Optics 4-pass, 3000-3600 MeV phase adv. still larger then 180 deg. in both planes 5-pass, 3600-4200 MeV EUROnu Annual Meeting, CERN, March 26, 2009
Mirror-symmetric ‘Droplet’ Arc – Optics (bout = bin and aout = -ain , matched to the linacs) E =1.2 GeV 2 cells out transition 2 cells out transition 10 cells in EUROnu Annual Meeting, CERN, March 26, 2009
‘Droplet’ Arcs scaling – RLA I • Fixed dipole field: Bi =10.5 kGauss • Quadrupole strength scaled with momentum: Gi = × 0.4 kGauss/cm • Arc circumference increases by: (1+1+5) × 6 m = 42 m EUROnu Annual Meeting, CERN, March 26, 2009
Mirror-symmetric ‘Droplet’ Arc – Optics Arc1 (E =1.2 GeV) 10 cells in 2 cells out 2 cells out Arc2 (E =1.8 GeV) 15 cells in 3 cells out 3 cells out EUROnu Annual Meeting, CERN, March 26, 2009
Linac ½-to-Arc1 – Beta Match E =1.2 GeV • Already matched ‘by design’ • 900 phase adv/cell maintained across the ‘junction’ • No chromatic corrections needed EUROnu Annual Meeting, CERN, March 26, 2009
Linac1-to-Arc2 – Beta Match E =1.8 GeV • Noticeable mis-match at the end of Linac1 • ‘Matching quads’ are invoked EUROnu Annual Meeting, CERN, March 26, 2009
Linac1-to-Arc2 – Beta Match E =1.8 GeV • No 900 phase adv/cell maintained across the ‘junction’ • Chromatic corrections needed EUROnu Annual Meeting, CERN, March 26, 2009
Linac1-to-Arc2 – Chromatic compensation E =1.8 GeV • Chromatic corrections with two pairs of sextupoles EUROnu Annual Meeting, CERN, March 26, 2009
Linac1-to-Arc2 - Chromatic Corrections initial uncorrected two families of sextupoles EUROnu Annual Meeting, CERN, March 26, 2009
‘Droplet’ Arcs scaling – RLA II • Fixed dipole field: Bi = 40.3 kGauss • Quadrupole strength scaled with momentum: Gi = × 1.5 kGauss/cm • Arc circumference increases by: (1+1+5) × 12 m = 84 m EUROnu Annual Meeting, CERN, March 26, 2009
RLA II - linac Optics mirror symmetric quads in the linac 1-pass, 4.6 -6.6 GeV Quad gradient length EUROnu Annual Meeting, CERN, March 26, 2009
Work Plan EUROnu Annual Meeting, CERN, March 26, 2009
Work Plan cont. EUROnu Annual Meeting, CERN, March 26, 2009
Summary • IDS Goals – laying engineering design foundation • Define beamlines/lattices for all components • Design lattices for transfer lines between the components • Resolve physical interferences, beamline crossings etc Floor Coordinates • Chromatic corrections with sextupoles implemented • Presently completed Optics design • Pre-accelerator (244 MeV-0.9) + injection double chicane • RLA I (0.9-3.6 GeV) and RLA II (3.6-12.6 GeV) • 4.5 pass linac • Droplet Arcs1-4 • Still to do…. • End-to-end simulation • Engineer individual active elements (magnets and RF cryo modules) • Element count and costing EUROnu Annual Meeting, CERN, March 26, 2009