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Super Beam Simulation: radiation/activity, dose rates issues towards costing
Talk’s Layout:
Material quantities for the SuperBeam Layout
Activities for target and Dose rates for a single target/horn for different cooling times at storage area
4horn layout: dose rates in target/horn station and preliminary activity study in the rock (molasse) surround it
Conclusions/Future
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Material for SuperBeam
1st order SuperBeam layout beam (based on T2K design) : no service/power supply galleries and collimators, no proton beam tunnel.
Requirements: concrete to confine all/most of the energy deposited by secondary particles
• minimize the activation in the rock (molasse) and the dose rotes of other galleries • minimum activation at the edge of the concrete
concrete
Fe for shields, vessels and DT graphite for
beam dump
rock: molasse@CERN
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Tables for different Material
concrete shields Fe: vessels, shields graphiteDownstream 1.95target/horn gallery 3.4 0.2Decay Tunnel 11 0.04Beam Dump 5 .8 3Total in kt 21.35 1.04 3
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Super Beam layout
Design includes: Proton Driver line Experimental Hall
MW Target Station Decay Tunnel Beam Dump
Maintenance Room Service Gallery
Power supply Cooling system Air-Ventilation system
Waste Area
deca
y tu
nnel
(25
m)
spare area
beam
target/horn station
shielding
beam dump
horn power supply and electronics
gallery
hot cell
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Target Activity at Storage Area study set up: packed Ti target, 66%dTi
1.3MW beam, 200days of irradiation no other activation at storage area
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radiation limits as in CNGS notes:
rates (e.g.):at 60cm distance from the outer conductor (calculation of the rates using 20cmx20cmx20cm grid binning through out the layout -> choose a slice of x-axis with 20cm thickness and 60cm away )
Dose Rates for target/horn at Storage Area, I
Limits per 12-months period (mSv)Public Workers
France < 1 < 20Switzerland < 1 < 20CERN < 0.3 < 20, if .gt. 2mSv/month
report to Swiss authorities
plotsz
x
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Dose Rates target/horn at Storage Area, II
1month 1year
50years 100years
high effective dose rates for the target/horn system makes them inaccessible for humans for years -> remote handling mandatory horn to be studied separately from the target results in agreement with older CERN’s 4MW beam studies, NIM A 545 (2005) 813-822
palette in mSv/h
> 50 mSv/h
> 0.01 mSv/h
> 1 Sv/h
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Dose Equivalent Rate contribution (cooling time 1d)
0.000E+00
2.000E+10
4.000E+10
6.000E+10
8.000E+10
1.000E+11
1.200E+11
1.400E+11
1.600E+11
1.800E+11
0 20 40 60 80 100 120 140 160
All
Target
Horn
Vessel
Tunnel
89%
7% 4% 0%
Target
Horn
Vessel
Tunnel
Distance (cm) All Target Horn Vessel Tunnel*
60 554400 469800 38304 21722.4 82.152
100 240948 213660 15933.6 20746.8 3664.8
140 157716 123372 11300.4 18478.8 418.32
DER Estimation mSv/h
Fluka parameter Inputs : Proton Energy : 4.5 Gev Beam Intensity : 5.56*1015 protons Irradiation times : 200 days
First Step : 10000 Histories Second Step : 2000000 Histories
=> Increase statistics *Vessel act as a shield
DER Evolution with distance DER Contribution to the dose at 60cm
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Activation in the rock around the SuperBeam layout(full 4horn simulation, medium stats: 106 protons, 20% error)
study set up: packed Ti target, 66%dTi
4MW beam, 4horns, 200days of irradiationaim: to confine the energy using concrete around the apparatus -> minimize the activation of the rock (molasse) minimum activation leads to minimum water contamination concrete thickness will determine the activation of the molasse of all the radionuclide's created 22 Na, tritium could represent a hazard by contaminating the ground water. Limits in activity after 1y=200days of beam:
CERN annual radionuclide release to water constraints (achieve 0.3mSv for the public)
SuperBeam, (preliminary)
22 Na 4.2 x 1011 Bq - (to be investigated)tritium 3.1 x 1015 Bq 6x108 Bq
activation plots
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Activation and Energy Plots
molasse
concrete
molasse
concrete energy is confined from concrete thickness minimum activation of molasse rock minimum/none effective dose to humans in other galleries detailed tables of the radionuclides water contamination from tritium is well kept under safety levels
ACTIVITY in Bq/cm3
POWER in kW/cm3
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ACTIVITY in Bq/cm3
ACTIVITY in Bq/cm3
with iron shield shield to protect service galleries additional cost
rock: molasse@CERN
concrete
Fe for shields, vessels and DT
graphite for beam dump
iron shields for service galleries
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study set up: 4MW beam, packed Ti target, 66%dTi
4horns, 200days of irradiation
rates :A. at the start of the decay tunnel using a slice of beam/z-axis with 10cm
thicknessB. average dose rates along the beam/z-axis and x-axis(volume binning of 10cmx10cmx10cm on both cases)
shown from 1day to 6months, more cooling times and the effective dose along the layout are being simulated
Dose Rates in Target Horn Gallery
plots
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Dose at the start of the Decay Tunnel in transversal x-y plane
1day 1month
4months 6months
> 10 Sv/h > 10 Sv/h
> 1 Sv/h> 1 Sv/h
palette in mSv/h
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<Doses> in transversal and longitudinal planes for Target/Horn Gallery
palette in mSv/h
1month
1month
6months
6months
> 10 Sv/h > 1 Sv/h
> 10 Sv/h > 1 Sv/h
remote handling mandatory
x-y plane x-y plane
z-y plane z-y plane
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<doses> in longitudinal plane along beam axis
palette in mSv/h
1day6months
1year 10years
DT areaHorns
Beam Dump
Horns
Horns
Horns
DT area DT area
DT area
Beam Dump
Beam Dump
Beam Dump
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DT area
<doses> in longitudinal plane along beam axis
50years
100years
Horns Beam
Dump
Beam DumpHor
nsDT area
palette in mSv/h
highly effective doses drop after 50year or more4horn system with Ti highly activated and unapproachable for very long times as seen also in one horn example
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summary
minimum activation in molasse rock for current secondary beam layout
tritium does not present any hazard related to ground water, 22 Na to be investigated (preliminary)
high dose rates in Storage Gallery -> remote handling for repairs mandatory high dose rates along SuperBeam layout -> carefully design of shielding for the apparatus, remote handling for any part of the 4horn system
costing increase
Thanks