pre- linac simulations in g4beamline kevin b. beard muons,inc . & alex bogacz & yves ...

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Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Pre-Linac simulations in G4beamline

Kevin B. BeardMuons,Inc.

&Alex Bogacz & Yves Roblin

Jefferson Lab

LEMC2009 workshop 8-12 Jun 2009

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

0.6 GeV/pass 3.6 GeV

0.9 GeV244 MeV

146 m

79 m

2 GeV/pass

264 m

12.6 GeV

Etotal: 244 MeV → 900 MeV

P: 220 MeV/c → 894 MeV/c

KE: 138 MeV → 794 MeV

M = 105.658 MeV

pre-accelerator linac - not very relativistic

Morteza Aslaninejad, Cristian Bontoiu

Jürgen Pozimski, Ajit Kurup

Imperial College, London, UK

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

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

15

0-1

50

dP

/P *

10

00

,

Longitudinal phase-space tracking

IDS rmsA = (2.5)2

normalized emittance: x/y mmra

d

4.8 30

longitudinal emittance: l

lp z/mc)

momentum spread: p/p

bunch length: z

mm

mm

27

0.07

176

150

0.17

442

ELEGANT (Fieldmap) OptiM (Matrix)

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Solenoid Linac (244 -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

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

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

1460

Sat Dec 13 22:36:02 2008 OptiM - MAIN: - D:\IDS\PreLinac\Sol\Linac_sol.opt

120

50

BE

TA

_X&

Y[m

]

DIS

P_X

&Y

[m]

BETA_X BETA_Y DISP_X DISP_Y

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

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)

•http://g4beamline.muonsinc.com

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Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Solenoid Model (Superfish)

outer coil

inner coil

shield

2e

pc

22 2

edge z 0

-

1 k a= B (s) ds B L

2 8e

pc 0k = B

‘Soft-edge’ Solenoid

21Ls

a

z 0

1B (s) = B tanh

2

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Two-cell cavity (201 MHz) – COMSOL

Morteza Aslaninejad

Cristian Bontoiu

Jürgen Pozimski

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Field maps

Ez

single RF cell

Ez

solenoid

Bz

double RF cell

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

LEMC2009 workshop 8-12 Jun 2009

g4beamline 2.08

valve assembly

conductors

counterwoundsolenoid

RF cellVirtual detectors

flux return shield

stainless pipe

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

LEMC2009 workshop 8-12 Jun 2009

upper middle

lower

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

ΔE ≈ -2qEzo L cos(π/ 2β) cos(φ) β2/(π (1-β2)

L=2λ c=λf z=cβt

+L/2

-L/2

0o≡on crest

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

ΔE ≈ -2qEzo L cos(π/ 2β) cos(φ) β2/(π (1-β2)

ΔE ≈ ∫ Ez(z,z/cβ) dz

Ti ≈ Ti-1+ (zi - zi-1)/(cβi-1)

Simple Phasing via spreadsheet

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Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

Linac parameters

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

phases from spreadsheet

phases partially adjusted

Longitudinal

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

Comparison of GPT, OptiM, g4beamline

z[cm]

KE[MeV]

KE[MeV]

z[cm]

OptiM

G4beamline w/adj. φ's

G4beamlinew/OptiM's φ's

GPT

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

Ez

Ez

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

LEMC2009 workshop 8-12 Jun 2009

Sep 14, 2010Muons, Inc.

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

Pz

t

Synchrotron motion

t

~ 1 synch period

~ oncrest

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

GPT

G4beamline

z[m]z[m]

y[m]

Transverse motion

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

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)

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011

Linac – near term plans

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

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

Muons, Inc.Winter MAP Mtg, Mar. 2nd, 2011Muons, Inc.

LEMC2009 workshop 8-12 Jun 2009

Sep 14, 2010