1. Modeling the Upper, Middle, & Lower
NF linac in G4beamline
Kevin B. Beard,
Muons,Inc.
&
Alex Bogacz,
Jefferson Lab
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

2. Neutrino Factory ~ 25 GeV
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

3. Muon Collider ~ 1.5 TeV
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

4. pre-accelerator linac - not very relativistic
Morteza Aslaninejad, Cristian Bontoiu
Jürgen Pozimski, Ajit Kurup
Imperial College, London, UK
0.6 GeV/pass
3.6 GeV
0.9 GeV
244 MeV
146 m
79 m
2 GeV/pass
264 m
12.6 GeV
Mm = MeV
Etotal: 244 MeV → 900 MeV
P: MeV/c → 894 MeV/c
KE: MeV → 794 MeV
εTN ~ 40,000 mm-mr
Δp/p ~ 17%
Δφ ~ +/- 102o RF
Muons, Inc.

5. Why another simulation?
OptiM – fast, interactive, design, matrix based 0th order design tool, symplectic soft edge solenoids, very good at tuning (free)
GPT – good at tracking ($)
G4beamline – tracking, Geant4 particle decays & interactions, energy depositions, showers, etc., not so good at tuning (free & open source)
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

6. Linear Pre-accelerator – 244 MeV to 909 MeV
6 short cryos
15 MV/m
8 medium cryos
17 MV/m
11 long cryos
1.1 Tesla solenoid
1.4 Tesla solenoid
2.4 Tesla solenoid
Transverse acceptance (normalized): (2.5)2= 30 mm rad
Longitudinal acceptance: (2.5)2 pz/mc= 150 mm 8m 3m 5m
Mini-workshop on Low Energy Muon Acceleration, CNU, February 2-5 , 2010

7. Solenoid Model (Superfish)
outer coil
shield
inner coil
‘Soft-edge’ Solenoid

8. Two-cell cavity (201 MHz) – COMSOL
Morteza Aslaninejad
Cristian Bontoiu
Jürgen Pozimski

9. Field maps single RF cell solenoid Ez Bz double RF cell Ez Bx,By
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.
MAG, Aug 31, 2010

10. g4beamline 2.02 valve assembly conductor RF cell
counterwound
solenoid &
flux return shield
RF cell
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.
MAG, Aug 10, 2010

11. g4beamline 2.08
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

12. LEMC2009 workshop 8-12 Jun 2009
Aug 31, 2010
Muons, Inc.

13. Simple Phasing via spreadsheet
0ₒ≡on crest
L=2λ c=λf z=cβt
Ez(z,t) ≈ qEzo cos(2πf t + φ) cos(π z/L)
+L/2
ΔE ≈ ∫ Ez(z,z/cβ) dz
-L/2
ΔE ≈ -2qEzo L cos(π/ 2β) cos(φ) β2/(π (1-β2)
ΔE ≈ -2qEzo L cos(π/ 2β) cos(φ) β2/(π (1-β2)
Ti ≈ Ti-1+ (zi - zi-1)/(cβi-1)
LEMC2009 workshop 8-12 Jun 2009
Aug 31, 2010
Muons, Inc.
Muons, Inc.
ΔE ≈ ∫ Ez(z,z/cβ) dz
Ez(z,t) ≈ qEzo cos(2πf t + φ) cos(π z/L)
Ti ≈ Ti-1+ (zi - zi-1)/(cβi-1)

14. Linac parameters
Muons, Inc.

15. phases partially adjusted
Longitudinal
phases partially adjusted
phases from spreadsheet
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

16. Comparison of GPT, OptiM, g4beamline
KE[MeV]
z[cm]
G4beamline w/adj. φ's
OptiM
G4beamline
w/OptiM's φ's
KE[MeV]
LEMC2009 workshop 8-12 Jun 2009
z[cm]
Muons, Inc.

17. Ez Ez
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

18. LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

19. Fine tuning is still in progress
Synchrotron motion Pz
~ oncrest
~ 1 synch period
LEMC2009 workshop 8-12 Jun 2009 t t
Muons, Inc.
G4beamline model is working well and in general agreement with other simulations
Essential step toward our long term goal of complete end-to-end simulations
Fine tuning is still in progress
Will soon begin particle interactions with the hardware

20. Transverse motion GPT G4beamline y[m] LEMC2009 workshop 8-12 Jun 2009
z[m]
z[m]
Muons, Inc.

21. G4beamline improvements from this work:
fieldmap timeOffset fixed
(simple bug fix)
pillbox autoTune being added
(tune for max,min ΔE or Δt rather than assume Δv=0)
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.

22. Linac – near term plans optical rematch of linac to cooling channel
greatly improve RF phasing capability of G4beamline
optical rematch of linac to cooling channel
optimize longitudinal and transverse acceptance
determine energy deposition in components
prepare the transfer line to RLA I

23. LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.