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SLAC RP current activities in radiation simulation and possible extension to ILC

A. Fassò, N. Nakao, H. Vincke

Aug. 2, 2005

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Our tools

FLUKA and MARS Coupled electromagnetic/hadronic cascade Electric and magnetic fields Complex geometries Energy range keV to 1000 TeV Standard simulation tools for LHC

Benchmarking Neutron spectrometry Activation measurements

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Current and already planned simulation studies in RP

LCLS: shielding PPS stoppers radiation damage to electronics, permanent magnets,

diagnostic equipment soil, groundwater and air activation, penetrations, maze

design ….. ILC:

SC cavity dark current radiation damage positron target, dpa calculations in

collaboration with B. Wirth (LBL)

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FLUKA modelling of the LCLS undulator

Section of the geometry between two segments

AUTOCAD view

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Longitudinal and vertical distribution of total dose. Max = 110 Mrad/day

(assuming an electron intensity of 9.16 × 1011 electron/s)

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Transversal distribution of dose and neutron flux

At dose max At neutron flux max

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MARS15 Monte Carlo simulation for LCLS

Secondary particle shower By beam loss at BYD1 bending magnet14.1 GeV electrons Bending into the beam dump

Arrangement of beam line components and magnetic fields in MARS15

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Prompt dose distribution in LCLS tunnel by MARS15

14.1GeV 30W beam loss at BYD1-bending magnet

Vertical

Top view

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Residual Dose Rate & Activity around Beam Dump by MARS15

Along the beam line Perpendicular to beam line

Below 1 mrem/h at top concrete

3H (Tritium) & 22Na activities in soil are available from MARS15 simulation results

Activity estimation in ground water

1/100

Attenuation of residual dose rate in concrete and iron

Bottom side side forward 0.22 0.60 0.19 0.69 Bq/cm3

Residual Dose Rate [mSv/h] (30-day operation 1-day cooling

14.1GeV 5kW electron beam

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FLUKA Calculation for LCLS “Two mirror system”

Cross-sectional view through the FLUKA geometry.FEE...Front End Enclosure; WBOR…White Beam Optic Room; NEH…Near Experimental Hall.

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LCLS – “Two mirror system” - cont’d

Total effective dose rate in mrem/h

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Estimate of induced radioactivity around the FFTB dump

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Residual radioactivity around the FFTB dump after 180

days of operation (28.5 GeV electrons on dump, 2kW)

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

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Previous calculations performed for NLC by RP/SLAC

Dose to Electronics in the NLC Beam Tunnel RP Note 99–15

Soil & Groundwater Activation around the Beam Delivery System Tunnel RP Note 00-04

Evaluation of Radiological Consequences from Air Activation at NLC BDS Tunnel RP Note 00-05

Radiation Damage to Electronics Installed in Niches of the NLC Beam Tunnel RP Note 00–06

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RADIATION DAMAGE TO ELECTRONICS IN THE BEAM TUNNEL OF THE NEXT LINEAR COLLIDER1

- Non-radiation-hard electronics could be severelydamaged unless sufficiently shielded against radiation.- Proposal: Niches in the beam tunnel wall which are shielded by layers of polyethylene.

1 SLAC-PUB-8490

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ILC: Possibilities for the next calculations

Soil, air and groundwater activation Machine component activation Detector Background Shielding (personnel, environment, equipment) Dumps, collimators SC Quenching dose rates in occupied areas Anything else ?