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Induced radiation in ATLAS - an update
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V. Hedberg - Univ. of Lund The CERN Radiation Protection Committee - 21.05.2003 1 Induced radiation in ATLAS - an update MAIN CONCLUSIONS FROM THE PRESENTATION A YEAR AGO: ATLAS predicts that the beampipe will become a major source of induced radioactivity giving contact dose rates of up to 6 mSv/h ATLAS has two complicated access scenarios. in one (inner detector access) but not in the other (standard access). and full body dose rates of up to 0.5 mSv/h. The main difference between the two is that the beampipe is removed Changing the material of the beampipe from stainless steel to Aluminium could significantly reduce the radiation from the beampipe.
Transcript of Induced radiation in ATLAS - an update
V. Hedberg - Univ. of Lund The CERN Radiation Protection Committee - 21.05.2003 1
Induced radiation in ATLAS - an update
MAIN CONCLUSIONS FROM THE PRESENTATION A YEAR AGO:
ATLAS predicts that the beampipe will become a major source of induced radioactivity giving contact dose rates of up to 6 mSv/h
ATLAS has two complicated access scenarios.
in one (inner detector access) but not in the other (standard access).
and full body dose rates of up to 0.5 mSv/h.
The main difference between the two is that the beampipe is removed
Changing the material of the beampipe from stainless steel toAluminium could significantly reduce the radiation from the beampipe.
V. Hedberg - Univ. of Lund The CERN Radiation Protection Committee - 21.05.2003 2
Present status
Calculations of induced radiation:
Access equipment (scaffolding etc):
Special tooling for beampipe removal etc:
Changing the material of the beampipe:
Estimations of maintenance times:
Changing the thickness of the beamipe:
Temporary shielding:
WorkDone
Work inprogress
Discussion stage
V. Hedberg - Univ. of Lund The CERN Radiation Protection Committee - 21.05.2003 3
Method and assumptions
λ ϕA= n (1-e ) e σ-- λT t(Ε)(Ε) dE
Activity:
Particle flux maps
Cross sections
Input:
Material and geometry description of the experiment
Number of target nuclei
Running
Decay constant
timeCooling-off time
The programs DOT-III and MCNP are used to calculate self-absorption and photon transport.
34(PHOJET + GCALOR with luminosity 10 cm /s)
(Proton cross sections are used for all hadrons > 20 MeV)
(LHC year = 120 days of continous running)
( - radiation is not calculated)
Σ
β
Reactions givinga radioactive nuclei.
2{
4
ELECTROMAGNETIC CALORIMETER HADRONIC CALORIMETER MUON DETECTOR
BARREL ENDCAP BARREL ENDCAP BARREL ENDCAP
MAGNETS: BARREL TOROID SOLENOID ENDCAP TOROID20500 A - 4 TESLA 6000 A - 2 TESLA 20500 A - 4 TESLA
Accordeon lead absorbers Accordeon lead absorbers Flat iron absorbers Flat Copper absorbers Liquid Argon Liquid Argon Scintillator Tiles Liquid Argon
INNER DETECTOR
TAS COLLIMATORFORWARD SHIELDING
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MUON DETECTORS
TAS COLLIMATOR
Inner detector
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● 2113
Bellows 1 mm SS at R=40 mm 1.5 mm SS at R=60 mm 5 mm Aluminium
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236
● 504
● 86
● 34
● 23
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●500
392
●239
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445 (100d)856 (30d)2008 (5d)2329 (3d)
Dose rates in Sv/h after 100 days of µ running and 1 day of cooling
1m
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MUONS
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Dose rates in Sv/h after 100 days of µ running and 5 day of cooling
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Inner Detector
9 ACCESS
HAD
EM
INNER
QUADTAS
JNose
ForwardToroid
JToroid
ForwardToroid
Standard Access
ACCESS
LAr Cal
HAD
FCALJM
AEJ
CRANE ACCESS
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Beampipe
Inner Detector
Calorimeter Electronics
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Dose rates in Sv/h from the VA beampipe afterµ 100 days of running and 5 days of cooling.
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Inner detector access
INNER DETECTOR
CRANE ACCESS
The inner detector platform
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Inner Detector
Endcap
Calorimeter
Barrel
Calorimeter
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EMEC HEC 1 HEC 2
FCAL 3FCAL 1 FCAL 2
Dose rates in Sv/h after 100 days of running and 5 days cooling µ
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Dose rates in Sv/h from the beampipe, theµ
100 days of running and 5 days of cooling. inner detector and the LAr calorimeter after
TRT
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pp 1
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LAr Cal
HADHAD
EM
FCALJM
AEJ
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Rails
ACCESS
INNER DETECTOR
Removal of the pixel detector
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Dose rates in Sv/h from the pixel detector afterµ 10 years of running and 15 days of cooling.
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LAr Cal
HADHAD
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removed
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V. Hedberg - Univ. of Lund The CERN Radiation Protection Committee - 21.05.2003 23
Conclusions
The project of estimating the induced radiation in ATLASis finshed.
Work has been done on the scaffolding and platforms neededfor the various maintenance operations.
New radiation maps for various maintenance scenarios ofthe Inner detector has been calculated. The predicted dose rates are typically 10-40 µSv/h after high luminosity running.
More effort is needed on special tooling, temporary shielding etc.
For details about the activation calculations see http://atlasinfo.cern.ch/Atlas/TCOORD/Activities/CommonSys/Shielding/Activation/activation.html
