Shielding Studies usingMARS Monte Carlo code

Noriaki Nakao (SLAC)

Jan. 6, 2005, WORKSHOP Machine-Detector Interface at ILC, SLAC

Shielding Calculations by MARS code

J-PARC 3GeV Proton Synchrotron (2001)

SLAC LCLS 14.1GeV electron dump line (2004)

Foil position

36.08

71.92

116.11

152.197

188.035

268.308

304.146

223.873

Injection

Extraction

Arc-2

Arc-1Arc-3

RF

CollimatorL3BT

3NBT

Kicker

0m (348.333)

unit:[m]

J-PARC 3GeV Proton Synchrotron

MARS14 (2001) Distributed beam loss

using STRUCT (multi-turn tracking code) Beam line structure

using MAD-MARS beam line builder Deep penetration calculation

using 3-dimensional multi layer technique

Prompt & Residual dose rate estimation

Shield thickness adjustment

Foil position

36.08

71.92

116.11

152.197

188.035

268.308

304.146

223.873

Injection

Extraction

Arc-2

Arc-1Arc-3

RF

CollimatorL3BT

3NBT

Kicker

0m (348.333)

unit:[m]MARScalculationgeometry

J-PARC 3GeV Synchrotron

Tunnel Cross Section at Injection and Collimator Region

Vertical

Horizontal

Beam loss distribution (Injection-collimator region)

inwardoutward

unit:[m]

340.77 344.67

1.3

1.3

conc 0.2

iron 0.4

conc 0.2

1.2

1.2

ceilling

floor

conc 0.25iron 0.3

conc 0.25

3.2

1.2

Bump Bump

Septum

inward

outward

①②

③

④⑥⑦

beam line

beam loss

beam loss

yokeyokeyoke

SUS

Coil

Iron

Beam loss at injection septum

vertical

Horizontal

Injection septum

Arc region geometry

Magnetic fields

Bending DipoleFocusing or Defocusing

Quadrupole

Flux estimation cells for MARS14 calculation

(n)1.0

(c) 6.0

(e)4.5

4.1

(l)2.2

(k)5.7

(o)2.0

(a)3.2

(d)1.2

(f)2.4 (g)2.2(b)4.7

(m)1.0

(h)3.0

(j)2.5(i)3.5

unit:[m]

inward outwardceiling

floor

sub-tunnel

ground level

SOIL

CONCRETE

AIR

IRONLocalShield

flux detectors

11.8

1st layerBeam line module &Tunnel inside shield

3 dimensional multi layer calculationfor deep penetration

Leakage particles of previous layer

are used as sourceIn 10 times multiplied

Store information ofthe particles leaked

from geometry boundary(x,y,z,dx,dy,dz,E,W)

Leakage particles of previous layer

are used as sourceof 10 times multiplied

(splitting method)

Store information ofthe particles leaked

from geometry boundary(x,y,z,dx,dy,dz,E,W)

1st layerBeam line module &Tunnel inside shield

2nd layerTunnel outside shield

3 dimensional multi layer calculationfor deep penetration

1st layerBeam line module &Tunnel inside shield

2nd layerTunnel outside shield

3rd layerSoil around tunnel

Leakage particles of previous layer

are used as sourceof 10 times multiplied

(splitting method)

Store information ofthe particles leaked

from geometry boundary(x,y,z,dx,dy,dz,E,W)

3 dimensional multi layer calculationfor deep penetration

1st layerBeam line module &Tunnel inside shield

2nd layerTunnel outside shield

3rd layerSoil around tunnel

Last layerSoil below ground level

Leakage particles of previous layer

are used as sourceof 10 times multiplied

(splitting method)

Store information ofthe particles leaked

from geometry boundary(x,y,z,dx,dy,dz,E,W)

3 dimensional multi layer calculationfor deep penetration

Ground level

0.25Sv/h(0.025mrem/h)

5mSv/h(500mrem/h)

Prom

pt d

ose

rate

[m

Sv/h

]

SLAC LCLS - 14.1 GeV electron dump line

MARS15(2004) Consider

- Shielding, magnet, spoiler, collimator

- Magnetic field

Beam loss at (1) dump or (2) magnet

Dose & particle flux distribution (color 2D)

Horizontal view

Vertical view

30m

Overview of MARS15 geometry for LCLS dump line

SOIL

SOIL

AIR

Concrete

Muonshield

Muonshield

Hutch

Hutch

Beamdump

AIR

AIRMuonshield

Muonshield

Verticalcross section

BYD1-3Vetical Bending

pcpm1

Spoiller pm1-3

Quad

Dump

MuonShield

pcpm

2Synchrotronradiations14.1GeV

electronbeam

SOIL

CONCRETE

AIR

IRON

CONCRETE

CONCRETE

AL

(1) 14.1 GeV-5kW electrons into the beam dump

Verticalcross section

BYD1-3Vetical Bending Magnets

pcpm1

B en t e lec tron b eam

Synchrotronradiations

14.1GeVelectron

beam

Residual dose rate [mSv/h]30 day operation, 1 day cooling

Muon flux [1/cm2/sec]

Muon Flux

Residual dose rate and muon flux around Beam dump(14.1GeV 5kW electron beam)

Residual dose rate

Photon flux [1/cm2/sec] Electron flux [1/cm2/sec]

Neutron flux [1/cm2/sec] Prompt dose [mSv/h]

(2) 30W electron loss at bending magnet

Horizontal

Vertical

SUS pipe at Bending magnet

1mrad angle

Beam loss at SUS pipe of the 1st-bending magnet)

e+

e_

photon

injection angle = 1mrad

neutron

mu+

mu+

mu-mu-

e+

e_

Prompt dose[mSv/h]

Prompt dose

Muon FLux[1/cm2/sec]

Muon

Prompt dose and muon flux (14.1GeV 30W beam loss at 1st-bending magnet)

100 10 1 rem/h 100 10 1 0.1 mrem/h

Summary

Shielding studies were performed using MARS code for

- J-PARC 3GeV Proton Synchrotron - SLAC LCLS Dump line

Detailed structure of shielding, beam line modules, and magnetic fields were taken into account

Spatial distributions were obtained for prompt & residual dose rates, and particle flux (e, , , n etc.)