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HiRadMat Project – 2015-03
CERN
CH-1211 Geneva 23, Switzerland
Date: 06/02/16
Design Report
Concrete bunkers design for the HiRadMat
facility of CERN/SPS
Abstract
In order to protect the sensitive diagnostics equipment that are being used by the
experimental teams in HiRadMat facility, two concrete bunkers were designed and
optimized. The results of Monte-Carlo simulations as well as the final dimensions of the
bunkers are summarized in this report.
Prepared by :
Checked by :
Approved by :
N. Charitonidis, EN-MEF
N. Charitonidis, EN-MEF
I. Efthymiopoulos, EN-MEF
A. Fabich, EN-MEF
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HISTORY OF CHANGES
REV. NO.
DATE
PAGES
DESCRIPTION OF CHANGES
0.0
2012-02-08
4
First version, only the TJ7 bunker
1.0
2015-03-08
10
Update of the note for the new TT61 bunker
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TABLE OF CONTENTS
CONCRETE BUNKERS DESIGN FOR THE HIRADMAT FACILITY OF CERN/SPS ...1
1.
1.1
INTRODUCTION .......................................................................................4
HIRADMAT FACILITY OF CERN/SPS............................................................ 4
2.
2.1
2.2
CONCRETE BUNKERS ...............................................................................4
TJ7 BUNKER ........................................................................................... 5
TT61 BUNKER ......................................................................................... 6
3.
REFERENCES..........................................................................................10
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1. INTRODUCTION
1.1 HIRADMAT FACILITY OF CERN/SPS
The HiRadMat facility of CERN/SPS is a newly constructed facility at CERN where a
high-energy, pulsed beam is available for materials and accelerator components tests.
A full description of the facility can be found in [1]. A 3D model of the facility’s layout
can be seen in Figure 1.
Figure 1 — 3D drawing of the HiRadmat facility’s layout. The experimental area is
located in TNC tunnel, in front of the beam dump, while the experimental data
acquisition systems can be placed either in TJ7 or in TT61 tunnels.
2. CONCRETE BUNKERS
In order to protect sensitive experimental equipment from the prompt radiation, two
concrete bunkers have been designed and optimized using the FLUKA Monte – Carlo
code. The positions of the two bunkers can be seen in Figure 2.
Figure 2 — Top-view of HiRadMat facility. The positions of the two bunkers are
marked with the two red spots.
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2.1 TJ7 BUNKER
The dimensions of the bunker in TJ7 tunnel (distance ~ 35 m from the target) are
illustrated in Figure 3. The bunker material is concrete, with a nominal density of 2.4
g/cm3.
Figure 3 — Model of the concrete bunker placed in TJ7, with the corresponding
dimensions
In order to optimize the bunker’s dimensions, a set of Monte-Carlo simulations using
the FLUKA [2,3] code was performed. The simulation parameters are summarized in
Table 1. The fluence of Hadrons with energy > 20MeV was scored, for an assumed
HiRadMat pulse of 3.74x1012 protons, impinging on a tungsten powder target (density
9 g/cm3). The target was enclosed by two aluminium containers, as was the case for
the sample holder of HRMT-10 experiment [4]. The results of the simulations for the
camera (modelled roughly as a rectangular box of SiO2, and placed at the beam
height, behind the bunker) can be seen at Figure 4. A maximum fluence of
approximately 105 hadrons per pulse is scored on the camera.
Parameter
Beam Momentum
Beam sigma
Target
Equipment
Quantities Scored
Pulse Intensity
Value
440 GeV/c
0.5 mm x 0.5 mm
Cylinder of tungsten powder (9 g/cm3), R=1.6 cm, Length =
30 cm, enclosed into two aluminium containers.
1 silicon boxes 50 x 18 x 40 resembling the High Speed Camera
or other similar equipment placed at the beam height.
Dose (Gy), Hadrons > 20MeV Fluence (particles/cm2)
3.74 x 1012 protons
Table 1 — Simulation parameters for the optimization of the TJ7 bunker.
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~ 10
Hadrons/cm2/pulse
5
Statistical
Uncertainty: 3-6%
in the camera
Beam direction
Figure 4 — Hadrons > 20 MeV Fluence for 1 pulse of 3.74x1012 protons on target
does not exceed 105 hadrons/cm2
The absorbed dose by the camera is also of interest. In Figure 5, the maximum dose
deposited on the camera can be found, normalized for one pulse of 3.74x1012 protons.
A photo of the bunker in TJ7 can be seen in Figure 6.
2.2 TT61 BUNKER
During the LS1 technical stop, two feed-throughs were constructed between the TNC
and TT61 tunnels, in an attempt to reduce the optical paths between the observation
instruments and the target. For that reason, a new bunker was designed and
optimized in order to protect the experimental observation equipment from the
prompt radiation. More specifically, two positions of equipment placement have been
studied and optimized in TT61 tunnel, placed bilaterally from the feed through holes,
one upstream and one downstream the target.
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~ 2x10-4 Gy/pulse
Beam direction
Figure 5 — Maximum absorbed dose from the camera for one pulse of 3.74x1012 protons
on target (Gy), for the TJ7 bunker. The maximum dose does not exceed 2 x 10 -4 Gy.
Figure 6 — A photo of the bunker in TJ7.
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The new bunker dimensions can be seen in Figure 7.
Beam
Figure 7 — Top view drawing of the concrete bunker placed in TT61, with the
corresponding dimensions in mm. The height of the structure is 1.6 m.
The exact size was optimized with Monte-Carlo simulations, in order to achieve in the
camera the same hadrons > 20 MeV fluence (105 hadrons/cm3/3.74x1012 protons) as
in TJ7 bunker. The simulation parameters are summarized in Table 2.
Parameter
Value
Beam Momentum
Beam sigma
440 GeV/c
0.5 mm x 0.5 mm
Cylinder of solid tungsten (19 g/cm3), R=1.6 cm, Length = 30
cm, enclosed into two aluminium containers.
2 silicon boxes 50 x 18 x 40 resembling the High Speed Camera
or other similar equipment placed at the beam height.
Dose (Gy), Hadrons > 20MeV Fluence (Particles/cm2)
3.74 x 1012 protons
Target
Equipment
Quantities Scored
Pulse Intensity
Table 2 — Simulation parameters for the optimization of the TT61 bunker.
The results of the simulations for the fluence in the cameras (modelled roughly as
rectangular boxes of SiO2, and placed at the beam height) can be seen at Figure 8. A
maximum fluence of approximately 105 hadrons per pulse is scored on the camera
upstream the target, while a maximum fluence of 106 hadrons per pulse is scored on
the one downstream. The results for the absorbed dose, can be found in Figure 9,
normalized for 3 x1012 protons on target.
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~ 105
Hadrons/cm2/pulse
~ 106
Hadrons/cm2/pulse
downstream
feed-through
Upstream feedthrough
Target
Figure 8 — Top view of the bunker structure in TT61 tunnel. The hadron > 20 MeV
fluence in the upstream camera does not exceed 105 hadrons / cm2 per pulse.
However, the fluence in the downstream camera is calculated to be one order of
magnitude higher, that is 106 hadrons/cm2 per pulse.
Figure 9 — Maximum absorbed dose from the camera for one pulse of 3.74x10 12 protons
on target (Gy), for the TT61 bunker. The maximum dose does not exceed 10 -5 Gy in the
downstream camera and 10-4 Gy for the upstream one.
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3. REFERENCES
[1] I. Efthymiopoulos et al., “HiRadMat: A New Irradiation Facility for Material Testing at
CERN”, TUPS058, Proceedings of IPAC2011, San Sebastian, Spain
[2] T.T. Böhlen, F. Cerutti, M.P.W. Chin, A. Fassò, A. Ferrari, P.G. Ortega, A. Mairani, P.R.
Sala, G. Smirnov and V. Vlachoudis, "The FLUKA Code: Developments and Challenges for High
Energy and Medical Applications", Nuclear Data Sheets 120, 211-214 (2014)
[3] A. Ferrari, P.R. Sala, A. Fasso`, and J. Ranft, "FLUKA: a multi-particle transport code",
CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773
[4] O. Caretta, T. Davenne, C. Densham, M. Fitton, P. Loveridge, J. O’Dell, N. Charitonidis, I.
Efthymiopoulos, A. Fabich, and L. Rivkin, “Response of a tungsten powder target to an incident
high energy proton beam”, Phys. Rev. ST Accel. Beams 17, 101005