Radiation protection consideration for the IR upgrade

Doris Forkel-Wirth, Markus Fuerstner, Stefan Roesler

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Overview Introduction

Dose limits and ALARA Example: Job planning

Residual dose rates Simulation parameters Tunnel Inner triplet (Q1) TAS TAN

Summary

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Area classification

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ALARA

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requiredrecommended

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Example 1: IR7 – Job DosesCERN-SC-2005-093-RP-TN

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Example 1: IR7 – Job DosesCERN-SC-2005-093-RP-TN

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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FLUKA simulation Nominal LHC operation

Continuous operation for 180 days Average inelastic interaction rate 109 s-1

pp interaction - DPMJET3

Magnetic field CMS analytical solenoid field (*) 4 T Inner triplet field maps (**) Sep. dipole constant field 1.38 T

Cooling times 1 hour, 8 hours, 1 week, 1 month, 4 month

(*) Analytical solenoid updated by Francesco Cerrutti AB/ATB

(**) Field maps from Christine Hoa AT/MAS

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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FLUKA simulation (geometry)

TAS - Inner triplet - Dipole - JSCAA - TAN

TAS + inner triplet from Christine Hoa AT/MAS

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate IP5

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate Aisle

50 µSv/h

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate TAS

~70 mSv/h ~15 mSv/h

~5 mSv/h~10 mSv/h

TAS surface

TAS

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate Q1

~2.5 mSv/h ~1 mSv/h

~0.4 mSv/h ~0.2 mSv/h

Q1

Cryostat surface

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate TAN - 1

~ 1 mSv/h ~ 0.6 mSv/h

~ 0.4 mSv/h ~ 0.2 mSv/h

Aisle

TAN

July 31, 2008 LHC Interaction Regions Upgrade - Phase-I

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Residual dose rate TAN - 2

TAN

Aisle

70 µSv/h

Aisle

TAN

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Summary Detailed residual dose rate maps were calculated allowing to

optimize the interventions in terms of dose to personnel.

The dose rate maps can be verified with monitors of the RAMSES system (e.g. PMI) installed in the tunnel.

The area around the TAN, inner triplet and TAS will be highly radioactive. It will most likely be classified as limited-stay or high radiation areas. All installation will have to follow the rules and guidelines associated with such areas.

Optimization and the ALARA principle (are) will be essential parts of the design, operation and dismantling of any new accelerator, experiment or facility. During all phases in the life-cycle of the installation clear documentation is required that optimization rules have been followed.

Many open questions exist regarding the interventions, such as detailed intervention plans, individual and collective doses …