1. Muon RLA - Design Status and New Options
Alex Bogacz
Vasiliy Morozov, Yves Roblin, Jefferson Lab
Kevin Beard, Muons Inc.
MAP Winter Meeting, Jefferson Lab, March 2, 2011

2. Linac and RLAs - IDS IDS Goals: RLA with FFAG Arcs
244 MeV
0.6 GeV/pass
3.6 GeV
0.9 GeV
146 m
79 m
2 GeV/pass
264 m
12.6 GeV
79 m
Vasiliy Morozov
IDS Goals:
Define beamlines/lattices for all components
Matrix based end-to-end simulation (machine acceptance) (OptiM)
Field map based end-to-end simulation: ELEGANT, GPT and G4Beamline
Error sensitivity analysis
Component count and costing
Two regular droplet arcs replaced by one two-pass FFAG arc
K. Beard
Y. Roblin
C. Bontoui
MAP Winter Meeting, Jefferson Lab, March 2, 2011

3. Pre-Linac - Longitudinal phase-space
Initial distribution
ex/ey = 4.8 mm rad
el = sDp sz/mmc = 24 mm
ELEGANT (Fieldmap)
OptiM (Matrix)
MAP Winter Meeting, Jefferson Lab, March 2, 2011

4. Injection/Extraction Chicane
$Lc = 60 cm
$angH = 9 deg.
$BH = 10.2 kGauss
$Lc = 60 cm
$angV = 5 deg.
$BV = 4.7 kGauss m+
m+ m- m-
0.9 GeV
50 cm
1.7 m
2.1 GeV
1.5 GeV 30 1 -1
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
FODO lattice:
900/1200 (h/v) betatron phase adv. per cell
Double achromat Optics H -H V -V
3 cells
4 cells
MAP Winter Meeting, Jefferson Lab, March 2, 2011

5. Chicane - Double Achromat Optics30
0.5
PHASE_X&Y
Q_X
Q_Y
Dfx = 2p
Dfy = 2p
betatron phase 30 1 -1
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
Double achromat Optics
FODO quads:
L[cm] = 50
F: G[kG/cm] = 0.322
D: G[kG/cm] =
sextupole pair to correct vert. emittance dilution H -H V -V
3 cells
4 cells
MAP Winter Meeting, Jefferson Lab, March 2, 2011

6. Multi-pass Linac Optics – Bisected Linac
‘half pass’ , MeV
initial phase adv/cell 90 deg. scaling quads with energy 15 5
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
quad gradient
1-pass, MeV
mirror symmetric quads in the linac 15 5
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
quad gradient
MAP Winter Meeting, Jefferson Lab, March 2, 2011

7. Multi-pass bi-sected linac Optics 30 5
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
1.2 GeV
0.9 GeV
3.0 GeV
2.4 GeV
1.8 GeV
3.6 GeV
Arc 4
Arc 3
Arc 2
Arc 1
bx = 3.2 m by = 6.0 m
ax = ay =1.5
bx,y → bx,y
axy → - axy
bx = 6.3 m by = 7.9 m
ax = ay =1.3
bx = 7.9 m by = 8.7 m
ax = ay =1.3
bx = 13.0 m by = 14.4 m
ax = ay =1.5
quad grad.
length
MAP Winter Meeting, Jefferson Lab, March 2, 2011

8. Linac-to-Arc – Chromatic Compensation
E =1.8 GeV 72 15 3 -3
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y 15 3
BETA_X&Y[m]
DISP_X&Y[m] -3
BETA_X
BETA_Y
DISP_X
DISP_Y
‘Matching quads’ are invoked
No 900 phase adv/cell maintained across the ‘junction’
Chromatic corrections needed – two pairs of sextupoles
MAP Winter Meeting, Jefferson Lab, March 2, 2011

9. Linac-to-Arc - Chromatic Corrections
initial
uncorrected
two families of sextupoles 15 3 -3
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y 72
MAP Winter Meeting, Jefferson Lab, March 2, 2011

10. Mirror-symmetric ‘Droplet’ Arc – Optics
130 15 3 -3
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
E =1.2 GeV
(bout = bin and aout = -ain , matched to the linacs)
2 cells out
transition
2 cells out
10 cells in
transition
MAP Winter Meeting, Jefferson Lab, March 2, 2011

11. Alternative multi-pass linac Optics 90 5
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
1.2 GeV
0.9 GeV
3.0 GeV
2.4 GeV
1.8 GeV
3.6 GeV
Arc 1
Arc 4
Arc 3
Arc 2
bx = 3.2 m by = 6.0 m
ax = ay =1.5
bx,y → bx,y
axy → - axy
quad grad.
length
MAP Winter Meeting, Jefferson Lab, March 2, 2011

12. Arcs ‘Crossing’ - Vertical Bypassm+ m- 42 30 2 -2
BETA_X&Y[m]
DISP_X&Y[m]
BETA_X
BETA_Y
DISP_X
DISP_Y
4 vertical bends:
B = 1 Tesla
L = 10 cm
E = 1.2. GeV
Dy = 25 cm V -V
4 cells (900 FODO)
MAP Winter Meeting, Jefferson Lab, March 2, 2011

13. ‘Droplet’ Arcs scaling – RLA I
Ei [GeV]
pi/p1
cell_out
cell_in
length [m]
Arc1
1.2 1
2×2 10
130
Arc2
1.8
1.43
2×3 15
172
Arc3
2.4
1.87
2×4 20
214
Arc4
3.0
2.30
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
MAP Winter Meeting, Jefferson Lab, March 2, 2011

14. ‘Droplet’ Arcs scaling – RLA II
Ei [GeV]
pi/p1
cell_out
cell_in
length [m]
Arc1
4.6 1
2×2 10
260
Arc2
6.6
1.435
2×3 15
344
Arc3
8.6
1.870
2×4 20
428
Arc4
10.6
2.305
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
MAP Winter Meeting, Jefferson Lab, March 2, 2011

15. Component Count beamline RF cavities solenoids dipoles quads sext
1-cell
2-cell
pre-accelerator 6 62 25
inj-chic I
8+3 16 3
RLA I
linac 24 26
arc1 35 43
arc2 49 57 8
arc3 63 71
arc4 77 85
inj-chic II
RLA II 80 42
Lambertson 1
MAP Winter Meeting, Jefferson Lab, March 2, 2011

16. Summary
Piece-wise end-to-end simulation with OptiM/ELEGANT (transport codes)
Solenoid linac
Injection chicane I (new more compact design)
RLA I + Injection chicane II + RLA II
Chromaticity correction with sextupoles validated via tracking
Alternative multi-pass linac optics
Currently under study… GPT/G4beamline
End-to-end simulation with fringe fields (sol. & rf cav.)
Engineer individual active elements (magnets and RF cryo modules)
MAP Winter Meeting, Jefferson Lab, March 2, 2011

17. Backup slides
MAP Winter Meeting, Jefferson Lab, March 2, 2011

18. Initial phase-space after the cooling channel at 220 MeV/c
Linac-RLA Acceptance
Initial phase-space after the cooling channel at 220 MeV/c
ISS/IDS
erms
A = (2.5)2 e
normalized emittance: ex/ey
mmrad
4.8 30
longitudinal emittance: el
(el = sDp sz/mmc)
momentum spread: sDp/p
bunch length: sz mm 24
0.07
165
150
0.17
412
bx,y = 2.74 m
ax,y =
bg = 2.08
MAP Winter Meeting, Jefferson Lab, March 2, 2011