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
Sep 14, 2010
Muons, Inc.

2. 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
Mini-workshop on Low Energy Muon Acceleration, CNU, February 2-5 , 2010

3. Why another simulation?
OptiM – fast, matrix based, some issues with solenoids, very good at tuning (free)
GPT – good at tracking ($)
G4beamline – tracking + particle decays & interactions, energy depositions, showers, etc., not so good at tuning (free & open source)
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

4. Field maps single RF cell solenoid Ez Bz double RF cell Bx,By no B yet
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.
MAG, Aug 31, 2010

5. ... txt2blfieldmap LEMC2009 workshop 8-12 Jun 2009 Muons, Inc.
MAG, Jun 14, 2010

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

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

8. G4beamline input file z18.in
...
# The "default" physics list is QGSP_BERT
physics QGSP_BERT disable=Decay
###################### begin: common info #################################
# physical constants:
param deg= /180.
param muonmass=
param c_mm_nS=
upperCryomodule $Zcryo1 $j1 $Toff1 $kill1
upperCryomodule $Zcryo2 $j2 $Toff2 $kill2
upperCryomodule $Zcryo3 $j3 $Toff3 $kill3
upperCryomodule $Zcryo4 $j4 $Toff4 $kill4
upperCryomodule $Zcryo5 $j5 $Toff5 $kill5
upperCryomodule $Zcryo6 $j6 $Toff6 $kill6
middleCryomodule $Zcryo7 $j7 $Toff7 $kill7
middleCryomodule $Zcryo8 $j8 $Toff8 $kill8
middleCryomodule $Zcryo9 $j9 $Toff9 $kill9
middleCryomodule $Zcryo10 $j10 $Toff10 $kill10
middleCryomodule $Zcryo11 $j11 $Toff11 $kill11
middleCryomodule $Zcryo12 $j12 $Toff12 $kill12
middleCryomodule $Zcryo13 $j13 $Toff13 $kill13
middleCryomodule $Zcryo14 $j14 $Toff14 $kill14
lowerCryomodule $Zcryo15 $j15 $Toff15a $Toff15b $kill15
lowerCryomodule $Zcryo16 $j16 $Toff16a $Toff16b $kill16
lowerCryomodule $Zcryo17 $j17 $Toff17a $Toff17b $kill17
lowerCryomodule $Zcryo18 $j18 $Toff18a $Toff18b $kill18
lowerCryomodule $Zcryo19 $j19 $Toff19a $Toff19b $kill19
lowerCryomodule $Zcryo20 $j20 $Toff20a $Toff20b $kill20
lowerCryomodule $Zcryo21 $j21 $Toff21a $Toff21b $kill21
solenoid
RF timing
center
Only 534 non-comment lines, produces 244 virtual detectors, 25 cryomodules
beam stop
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

9. How G4beamline defines 0∘ LEMC2009 workshop 8-12 Jun 2009
Vary RF phases 0∘
90∘
180∘
How G4beamline defines 0∘
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.
MAG, Aug 10, 2010

10. Ez(z,t) ≈ qEzo cos(2πf t + φ) cos(π z/L)
Simple Phasing
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)

11. 1 line fix to BLCMDfieldmap.cc (ought to be in 2.04b)
G4beamline bug
xcmd: help fieldmap
fieldmap implements a field map, E and/or B, from a file.
Reads an input file in BLFieldMap format to define E and/or B
fields, optionally with time dependence. See the Users Guide for
a description of the BLFieldMap format.
Named Arguments (#=cannot be changed in place
filename Filename for the Field Map. #
file Synonym for filename. #
current Current of the
gradient Gradient of the
timeOffset Time offset (ns).
didn't work properly
1 line fix to BLCMDfieldmap.cc (ought to be in 2.04b)
local[3]-= timeOffset; /* KBB 25aug10 - shift time back by timeOffset */
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

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

13. phases partially adjusted
phases from spreadsheet
LEMC2009 workshop 8-12 Jun 2009
Aug 31, 2010
Muons, Inc.

14. IPAC2010 ∆E~10MeV/cell Pz0=220MeV/c transit=0.716
LEMC2009 workshop 8-12 Jun 2009
Muons, Inc.
MAG, Jun 14, 2010

15. retrack 1.17
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
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.
MAG, Jun 14, 2010

17. Pz [MeV/c] LEMC2009 workshop 8-12 Jun 2009 t[nS] Muons, Inc.
(bunches shifted for legibility)
LEMC2009 workshop 8-12 Jun 2009
t[nS]
Sep 14, 2010
Muons, Inc.

18. GPT G4beamline LEMC2009 workshop 8-12 Jun 2009 Muons, Inc.
Sep 14, 2010
Muons, Inc.

19. Optimizing with kmimf + G4beamline
Pz * Nm
cycle (G4beamline run#)
Sep 14, 2010
Muons, Inc.

20. Partially optimized ~ ½ lost
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

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

22. those that made it to the end in G4beamline
input t,Pz for acceptance
OptiM generated input
LEMC2009 workshop 8-12 Jun 2009
Sep 14, 2010
Muons, Inc.

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

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