radiation protection aspects for the phase ii upgrade

Radiation protection aspects for the Phase II upgrade

S. Roesler, C. Theis, C. Urscheler, Heinz Vincke, Helmut Vincke

Forum on Tracking Detector Mechanics 2013, 19-21 June

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OutlineA quick introduction to FLUKAResidual dose equivalent predictions by

FLUKA◦Evolution parameters for simulation◦Focus on Inner Detectors◦Scaling factors for Phase II upgrade◦Measured dose rates and comparison to

FLUKA simulations for ATLASALARA:

◦ALARA rules◦Optimization during design (ActiWiz)


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What is FLUKA1,2?General purpose tool for

calculating transport and interactions of particles with matter

Applications: accelerator shielding to target design, activation, dosimetry, detector design, etc.

(1) A. Ferrari, P.R. Sala, A. Fasso and J. Ranft. FLUKA: amulti-particle transport code. s.l. : CERN 2005-10, INFN/TC_05/11, SLAC-R-773, 2005.(2) G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S. Roesler, A. Fasso, J. Ranft. The FLUKA code: Description and benchmarking.

Proceedings of the Hadronic Shower Simulation Workshop 2006. s.l. : Fermilab 6-8Sept 2006, AIP Conference Proceeding 896, 31-49 (2007).


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Physics in FLUKA1,2interaction and transport of:

◦About 60 particles (non-nuclei) Photons and electrons from 1 keV to

thousands of TeV Hadrons up to 20 TeV (up to 10 PeV by

linking DPMJET3) Neutrons down to thermal energies (260 energy

groups for E < 20MeV)

Heavy ions◦In complex geometries and presence of

magnetic fields(1) A. Ferrari, P.R. Sala, A. Fasso and J. Ranft. FLUKA: a multi-particle transport code. s.l. : CERN

2005-10, INFN/TC_05/11, SLAC-R-773, 2005.(2) G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S. Roesler, A. Fasso, J. Ranft. The

FLUKA code: Description and benchmarking. Proceedings of the Hadronic Shower Simulation Workshop 2006. s.l. : Fermilab 6-8Sept 2006, AIP Conference Proceeding 896, 31-49 (2007).

(3) S.Roesler, R.Engel, J.Ranft. The Monte Carlo Event Generator DPMJET-III. s.l. : Springer-Verlag Berlin, 1033-1038 (2001), 2000. Vols. in Proceedings of the Monte Carlo 2000 Conference Lisbon, October 23-26.


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ATLAS model in FLUKA

(4) V.Vlachoudis "FLAIR: A Powerful But User Friendly Graphical Interface For FLUKA"Proc. Int. Conf. on Mathematics, Computational Methods & Reactor Physics (M&C 2009), Saratoga Springs, New York, 2009

Pixel

Pictured with FLAIR4

• Symmetry in φ and with regard to xy plane at IP • Including magnetic field from toroid• Reduced implementation of services and support

structure

10 m

Endcap calorimeter

TAS

Q1

Endcap toroid

Original version by: A. Ferrari, modified and updated by many other authors


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CMS model in FLUKA

(4) V.Vlachoudis "FLAIR: A Powerful But User Friendly Graphical Interface For FLUKA"Proc. Int. Conf. on Mathematics, Computational Methods & Reactor Physics (M&C 2009), Saratoga Springs, New York, 2009

Pictured with FLAIR4

• Symmetry in φ and with regard to XY plane in IP except for interface to LHC• Including magnetic field from solenoid and from Q1• Reduced implementation of services and support structure• No Castor

10 m

Pixel

HE

HF

TASQ1

Blockhouse

Original version by: M. Huhtinen, modified and updated by many other authors


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Operational scenario up to Phase II

2011&2012

LS1 2015 2016 2017 LS

2 2019 2020 2021 LS3

ATLAS Lint (fb-1) 31 52 41 41 83 83 83Lpeak (cm-2s-

1) 3×1033 1.0×1034

1.0×1034

1.0×1034

2.0×1034

2.0×1034

2.0×1034

CMS Lint (fb-1) 26 50 80 100 150 150 150Lpeak (cm-2s-

1) 8×1033 1.2×1034

2.3×1034

2.5×1034

3.5×1034

3.5×1034

3.5×1034

L.Rossi / Workshop on remote manipulations, 6.Mai 2013

Assumptions on the operational parameters as obtained from ATLAS and CMS


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Residual dose rates LS3 – ATLAS

one month

1 week 6 months

one year

0.5uSv/h

0.15uSv/h

0.3uSv/h

0.11uSv/h


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Residual dose rates LS3 – CMS

one month

1 week 6 months

one year

EDMS-Nr: 1281113

5uSv/h 1uSv/h

3uSv/h 0.7uSv/h


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TRTPixelSCT

ATLAS - inner detectors implementation in FLUKA

beampipe:• Be for z<3.5m,

aluminium for z>3.5m

• No bellows includedPixel layout• : by P. Miyagawa


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1 year6 months

4 weeks1 week

ATLAS - Residual Dose in vicinity of Inner detectors LS1


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1 year6 months

4 weeks1 week

ATLAS - Residual Dose in vicinity of Inner detectors LS3


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ATLAS - Scaling factors inner detectors (0<r<1m)

LS1 LS3


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ATLAS - Scaling factors inner detectors (0<r<1m)

Average scaling factors: residual dose at different cooling times

1w 1w/4w

1w/6m

1w/1y

LS1 1 0.7 0.3 0.2LS3 1 0.8 0.4 0.3

LS1 LS3


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ATLAS - Scaling factors LS1 to LS3

Average scaling factors: Residual dose LS1 vs LS3

1w 4w 6m 1y

LS3 / LS1 7.5 8.4 11 12


16Pictured with FLAIR

beampipe:• Be for z<2m, steel

for z>2mPixel layout• : by I.KurochkinTracker layout:• Si layers, average

material for services and air

Silicon tracker

ECAL barrel

HCAL barrel

ECAL endcap

Bellows (Fe, Cr, Ni)

CMS - inner detectors implementation in FLUKA


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6 months 1 year

1 week 4 weeks

CMS - Residual Dose in vicinity of Inner detectors LS1


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1 week 4 weeks

6 months 1 year

CMS - Residual Dose in vicinity of Inner detectors LS3


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CMS - Scaling factors inner detectors (0<r<1m)LS1 LS3


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Average scaling factors: residual dose at different cooling times

1w

1w/4w 1w/6m

1w/1y

LS1 1 0.5 0.2 0.1LS3 1 0.6 0.3 0.2

CMS - Scaling factors inner detectors (0<r<1m)LS1 LS3


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Average scaling factors: Residual dose LS1 vs LS3

1w 4w 6m 1y

LS3 / LS1 11 14 21 24

CMS - Scaling factors inner detectors


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Measurement points 1-5:

ATLAS – Bechmark to measured dose rates forward regionLS1


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Measurement points 1-5 @ 40cm:

MEASUREMENT / [µSv/h]

FLUKA / [µSv/h]

1 19 14 +- 22 10 14 +- 23 7.2 11 +- 24 47 42 +- 15 42 50 +- 1

ATLAS – Benchmark to measured dose rates forward regionLS1

Measurement data from 21.2.2013 in courtesy of O.Beltramello, N. Conan, S. Malyukov, G. Spigo


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6680 (EBC)Barre

l EBC40 cm 90 cm 180

cm

VI VA

6 87

MEASUREMENT / [µSv/h]

FLUKA / [µSv/h]

6 39 167 32 148 52 29

Measurement points 6-8 @ 10cm:

ATLAS – Benchmark to measured dose ratesLS1

Measurement data from 6.3.2013 in courtesy of O.Beltramello, N. Conan, S. Malyukov, G. SpigoDose equivalent rate prediction for VA by Z. Zajacova


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Classification of non-designated and radiation areas at CERN

EDMS-Nr: 810149

IEFC workshop 2011, 21 - 24 March 26

General Principles of Radiation Protection

1) Justification

any exposure of persons to ionizing radiation has to be justified

2) Limitation

the personal doses have to be kept below the legal limits

3) Optimization

the personal doses and collective doses have to be kept as low as reasonable achievable (ALARA)


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Optimization – CERN safety code F


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Optimization is legal requirement if accumulated annualdose exceeds 100 μSv (ALARA)

Optimization includes:

Optimization is done by the Experiment safety group (RSO, Glimos) in cooperation with CERN-RP group

• work coordination• work procedures• handling tools• design • material

5 mSvGro

up 1

crit

eria

Gro

up 2

crit

eria

Group 1 criteria: determine ALARA Level classificationGroup 2 criteria: can be used by RP/RSO to increase/decrease classification depending on radiological risk analysis

Formal work-and-dose-planning(DIMR) as from ALARA Level 2

ALARA committee if ALARA Level 3

Optimization – ALARA procedure

Methodology:1. Calculation of residual dose rate maps

2. Calculation of individual and collective intervention doses

3. Revision of design and/or work scenario

• for cooling times typical for interventions on the respective component• based on nominal operational parameters• definition of geometry and materials as detailed as needed (and available)

• Done by Experiment safety group (RSO, RPE, Glimos) approved by RP• based on as realistic as possible work scenarios, including locations, duration, number of persons involved,..• identification of cooling times below which work will be impossible (design criterion: 2 mSv/intervention/year)

• start with work steps that give highest individual or collective doses• consider optimization measures (distance, tooling, material choices, etc.)• identify if remote handling is possible

Optimization during design – Intervention doses

Forum on Tracking Detector Mechanics 2013, 19-21 June 29

Optimization starts with the design!


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Goal:• Minimize doses received by personnel during maintenance and repair• Reduce costs for waste disposal

Consider radiological hazards in the choice of construction materials

Tool to optimize material choices:

ActiWiz5 Computer code implementing a risk model using pre-calculated FLUKA results. Considers external exposure and radioactive waste disposal Provides radiological hazard assessment for arbitrary materials within a few seconds Catalogue6, produced with ActiWiz, listing pre-processed risk factors for typical accelerator construction materials as well as natural elements Web-based catalogue (ActiWeb) allowing user friendly comparison of pre-processed materials

Web-site: https://actiwiz.web.cern.ch/

Optimization during design – Material choice

(5) H. Vincke, C. Theis: “ActiWiz - optimizing your nuclide inventory at proton accelerators with a computer code, Proceedings of the ICRS-12 & RPSD 2012 conference, Nara, Progress in Nuclear Science and Technology, in press, 2013.(6) R. Froeschl, S, Sqobba, C. Theis, F. La Torre, H. Vincke, N. Walter: “Radiological hazard classification of material in CERN’s accelerators”, EDMS-Nr: 1184236


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ActiWiz web-based catalog

Pictures from: ActiWeb by F.L. Pereira, C. Theis, H. Vincke, (c) CERN 2011


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Pictures from: ActiWeb by F.L. Pereira, C. Theis, H. Vincke, (c) CERN 2011

ActiWiz web-based catalog

ActiWiz is designed for

LHC accelerator scenarios,

Keep in mind when using

for experiments


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Materials not available in the catalogue can be processed with ActiWiz

ActiWiz – Material Catalogue


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Optimization during design – ActiWiz


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Summary and Conclusion Ambient dose equivalent rate around inner detectors

for Phase II: up to 100 µSv/h after several months of cool down time

Scaling factors from LS1 to LS3 between 8-12 for ATLAS and 12-24 for CMS, depending on the cooling time

Benchmark with ATLAS measurements indicates factor of 2 for most locations with exceptions at local hotspots due to inaccurate geometry implementation

Future work: update FLUKA geometries including changes during LS1 (aluminium beampipe, implementation of missing flanges etc.)


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Backup slidesLS2


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6 months 1 year

4 weeks1 week

Residual Dose in vicinity of ATLAS Inner detectors LS2


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1 week 4 weeks

Residual Dose CMS Inner Detectors LS2

6 months 1 year


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BACKUP SLIDES ATLASResidual dose only pixelResidual dose only ID-SCT-TRT


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Residual Dose ATLAS Pixel LS1


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Residual Dose ATLAS Pixel LS3


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Residual Dose ATLAS ID-SCT-TRT LS1


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Residual Dose ATLAS ID-SCT-TRT LS3


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Waste zoning CMS

https://edms.cern.ch/document/1286671/1



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Waste zoning ATLAS



radiation protection aspects for the phase ii upgrade

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