Alex Bogacz

Operated by JSA for the U.S. Department of Energy

Thomas Jefferson National Accelerator Facility

Alex Bogacz EUROnu Annual Meeting, CERN, March 26, 2009

Alex Bogacz

Status and Plans for Linac and RLAs




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)




0.6 GeV/pass3.6 GeV

0.9 GeV244 MeV

146 m

79 m

2 GeV/pass

264 m12.6 GeV

Dogbone RLA - footprint

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Towards Engineering Design Foundation

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Tue Jun 10 21:06:52 2008 OptiM - MAIN: - D:\IDS\Arcs\Arc1.opt

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Alex Bogacz

RLA requirements Large transverse and longitudinal acceptances

Simultaneous acceleration of both + - 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

‘Dogbone’ RLA – Opportunities and Challenges




Linear Pre-accelerator – 244 MeV to 909 MeV

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

1460

Tue Feb 12 12:50:16 2008 OptiM - MAIN: - M:\casa\acc_phys\bogacz\IDS\PreLinac\Linac_sol.opt

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m]

Siz

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Y[c

m]

Ax_bet Ay_bet Ax_disp Ay_disp

Transverse acceptance (normalized): (2.5)2= 30 mm rad

Longitudinal acceptance: (2.5)2 pz/mc= 150 mm




Linear Pre-accelerator – 244 MeV to 909 MeV

1460

Tue Feb 12 12:50:16 2008 OptiM - MAIN: - M:\casa\acc_phys\bogacz\IDS\PreLinac\Linac_sol.opt

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m]

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m]

Ax_bet Ay_bet Ax_disp Ay_disp

Transverse acceptance (normalized): (2.5)2= 30 mm rad

Longitudinal acceptance: (2.5)2 pz/mc= 150 mm

26-26 S [cm] View at the lattice end

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0-1

60

dP

/P *

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00

,

25-25 S [cm] View at the lattice beginning

16

0-1

60

dP

/P *

10

00

,

Longitudinal phase-space (s, p/p) axis range: s = ±25 cm, p/p = ±0.2




Injection double-chicane

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Tue Mar 18 13:50:11 2008 OptiM - MAIN: - D:\IDS\Arcs\double_chicane3.opt

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Alex Bogacz EUROnu Annual Meeting, CERN, March 26, 2009NFMCC Collaboration Meeting, LBNL, January 27, 2009

Pre-accelerator–Chicane–Linac Matching

25-25 S [cm] View at the element 222

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/P *

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15-35 S [cm] View at the element 350

10

0-2

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dP

/P *

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Wed Jun 11 00:32:07 2008 OptiM - MAIN: - D:\IDS\PreLinac\Linac_sol_chicane_1.opt

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= 2×10-5




Multi-pass linac Optics

1-pass, 1200-1800 MeV

‘half pass’ , 900-1200 MeV initial phase adv/cell 90 deg. scaling quads with energy

mirror symmetric quads in the linac

39.91030

Fri Jan 23 14:33:20 2009 OptiM - MAIN: - N:\bogacz\IDS\Linacs_bisect\Linac05.opt

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quad gradient

quad gradient





2-pass, 1800-2400 MeV

3-pass, 2400-3000 MeV

phase adv. diminish uniformly in both planes

78.91030


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4-pass, 3000-3600 MeV

phase adv. still larger then 180 deg. in both planes

5-pass, 3600-4200 MeV

78.91030


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78.91030


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1300


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10 cells in2 cells out

2 cells out

footprint

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(out = in and out = -in , matched to the linacs)

transition

transition

E =1.2 GeV

40-40 S [cm] View at the lattice end

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dP

/P *

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40-40 S [cm] View at the lattice beginning

300

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dP/P

* 1

000,

Mirror-symmetric ‘Droplet’ Arc – Optics




‘Droplet’ Arcs scaling – RLA I

i = 1…4

Ei

[GeV]

pi/p1 cell_out

cell_in

length [m]

Arc1Arc1 1.2 1 2×2 10 130

Arc2Arc2 1.8 3/2 2×3 15 172

Arc3Arc3 2.4 2 2×4 20 214

Arc4Arc4 3.0 5/2 2×5 25 256

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

footprint

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Mirror-symmetric ‘Droplet’ Arc – Optics

Arc1 (E =1.2 GeV)

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2 cells out


3 cells out


Arc2 (E =1.8 GeV)




Linac ½-to-Arc1 – Beta Match

E =1.2 GeV

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Already matched ‘by design’

900 phase adv/cell maintained across the ‘junction’

No chromatic corrections needed

36.91030


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Linac1-to-Arc2 – Beta Match

E =1.8 GeV

Noticeable mis-match at the end of Linac1

‘Matching quads’ are invoked

36.91030

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Wed Jun 11 13:18:15 2008 OptiM - MAIN: - D:\IDS\Arcs\Arc2.opt

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Linac1-to-Arc2 – Beta Match

E =1.8 GeV

No 900 phase adv/cell maintained across the ‘junction’

Chromatic corrections needed

36.91030


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Wed Jun 11 14:08:34 2008 OptiM - MAIN: - D:\IDS\Arcs\Arc2_match.opt

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Linac1-to-Arc2 – Chromatic compensation

E =1.8 GeV

Chromatic corrections with two pairs of sextupoles

36.91030


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[ / ] 0.2 0.01 150 0.3 [ / ]sext

pG kGauss cm S D kGauss cm

p

10 [ / ]quadG kGauss cm




Linac1-to-Arc2 - Chromatic Corrections

30-30 X [cm] View at the lattice beginning

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30-30 X [cm] View at the lattice end

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30-30 X [cm] View at the lattice end

80

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X`[

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initial uncorrected two families of sextupoles

36.91030


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‘Droplet’ Arcs scaling – RLA II

i = 1…4

Ei

[GeV]

pi/p1 cell_out

cell_in

length [m]

Arc1Arc1 4.6 1 2×2 10 260

Arc2Arc2 6.6 3/2 2×3 15 344

Arc3Arc3 8.6 2 2×4 20 428

Arc4Arc4 10.6 5/2 2×5 25 512

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

footprint

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1-pass, 4.6 -6.6 GeV

RLA II - linac Optics

254.6510

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mirror symmetric quads in the linac

Quad gradient

length










Work Plan




Work Plan cont.




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

Documents

Alex Bogacz