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SIT Project Superconductor Irradiation Test. Work in the frame of the LHC Phase II Upgrade Previous work was dedicated to the study of the energy deposition in the low- b inner triplet and its best layout (A.Ferrari, F.Cerutti, A. Mereghetti, C.Hoa, E. Wildner …..). - PowerPoint PPT Presentation
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FLUKA Meeting Milan Jul 2010 [email protected]
0 10 20 30 40 50 60
-0.3
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-0.1
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Q3Q2bQ2aQ1
Collimator(TAS)
Detector Solenoid
Ho
rizo
nta
l co
ord
ina
te (
m)
Distance from I.P. (m)
0 10 20 30 40 50 60
-0.3
-0.2
-0.1
0.0
0.1
0.2
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Q3Q2bQ2aQ1
Collimator(TAS)
Detector Solenoid
Ho
rizo
nta
l co
ord
ina
te (
m)
Distance from I.P. (m)
Work in the frame of the LHC Phase II Upgrade Previous work was dedicated to the study of the energy deposition in the low- inner triplet and its best layout (A.Ferrari, F.Cerutti, A. Mereghetti, C.Hoa, E. Wildner …..)
Phase I : L= 2-3 x1034 cm-2s-1 (NbTi)
Phase II : L=1035 cm-2s-1 (Nb3Sn)
SIT Project
Superconductor Irradiation Test
Outline• Why Irradiation tests ?
• Beam needs
• Beam availability
• Geometry/energy deposition activation and cooling (no soldering)
• Soldering (negative) effect
• Next: Thermal analysis
DPA analysis
The magnetic elements close to the LHC IP will undergo to a heavy radiation load (At phase II it will be 10 times the the nominal one, being the Luminosity 10 times higher)
Ways of reducing the radiation load are the optimization of the optics, larger aperture magnets (100-200 mm with Nb3Sn technology), liners, protections, ….
It is necessary to do irradiation tests on Nb3Sn cable samples, in order to predict the behaviour/degradation “spot” and old data about the radiation damage un Nb3Sn
~1 MeV
E dN
dE (p
art.
coll.
-1 c
m-2
) The neutron energy fully covers a wide interval, down to thermal energies
Spectra in Q2a100 … 200 MeV
From F.Cerutti, A Mereghetti
neutrons damage conductor photons damage insulators protons have lower effects ?
Motivation for an R&D - 1/2
Last data available on LTS materials dates back to the 80’s, typically binary and non-optimized ternary Nb3Sn (500 A/mm2 at 12 T, 4.2 K).
Recent materials, especially highly optimized ternary Nb3Sn (3000 A/mm2 at 12 T, 4.2 K) may respond in a different manner.
Will JC increase/decrease significantly ? Will the strands remain magneto-thermally
stable, or become unstable (excess JC and reduced RRR) ?
From L. Bottura slides at EuCARD workshop on insulator irradiation, CERN, December 2, 2009
From L. Bottura slides at EuCARD workshop on insulator irradiation, CERN, December 2, 2009
Motivation for an R&D - 2/2
Most data was collected from experiments in research reactors, with typical energy spectrum in the range of thermal (0.025 eV) up to 14 MeV, peaked in the 1 MeV range
The expected peaks in the spectra of the radiation in the IR quads of Phase II upgrades will be significantly higher (e.g. protons at 100 MeV), and the particle species will be much more varied
Will the critical properties respond in a scalable manner to particle irradiation at much different energies ?
R&D program objectives
Examine the sensitivity of new materials (High-JC, optimized ternary Nb3Sn, MgB2 and HTS) and stabilizer (Cu) to LHC radiation (neutrons and protons) with distributions peaked at: 1 MeV neutrons
60 MeV protons
Significant tails at higher energy
This is a new domain for which very little and very scattered data exists
From L. Bottura slides at EuCARD workshop on insulator irradiation, CERN, December 2, 2009
Beam Sources (with cryogenic irradiation facility)
NEUTRONS:
• Reactors (Atominstitut in Wien, TRIGA)
• Secondary Neutrons from p on Be (at the cyclotron of the Kurchatov Institute)
PROTONS :
Cyclotron at Kurchatov Insitute
p beam
p on BeEp = 30 MeV Spot size = 2 cm FWHM
Be target (Cylinder) r = 5 cm, h = 2 cm 10 runs with 106 particles each
Neutron/pr Error %
Forward 1.344E-02 2.692E-01
Side 3.107E-03 5.656E-01
Back 1.016E-02 3.114E-01
S1
S3
S5
S7
S9
S11
0.E+00
2.E-05
4.E-05
6.E-05
8.E-05
1.E-04
Angle
Neutron (fw)/primary proton
Serie1
Serie2
Serie3
Serie4
Serie5
Serie6
Serie7
Serie8
Serie9
Serie10
Serie11
0
25.8
36.9
45.6
53.1
60
66.4
72.5
78.5
84.3
90
12.2 MeV<E<13.5 MeV
(9.5 +/- 0.32)E-05
p on Be
1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1
5.0x10-5
1.0x10-4
1.5x10-4
2.0x10-4
2.5x10-4
3.0x10-4
3.5x10-4
4.0x10-4
4.5x10-4
5.0x10-4
30 MeV protons on Be target
Target length = 2 cm
Neutrons
cm-2
pr-
1
Energy (GeV)
Forward neutrons Side " Backward "
Target radius = 5 cm
Values already multiplied for the energy, to have directly the number of neutrons/proton
“Double differential” spectrum
integrated spectrum (over angles)
With 20 a p current a total flux of 1.6x1012 n/s will be avalilable (fw) from such a target
Reactor fluxes ~ 1013 - 1014 n/cm2s
p on Be
Atominstitut reactor will provide n beam
The Sample Holder
Ti5
Nb3Sn cableSimpleGeo Plot
Ep = 30 MeV ; Spot size = 2 cm FWHM
Cooling LHe, LN2, H2O (closer beam origin in case of LN2 and H2O)
Cut-offs = 100 keV for hadrons, and 10 keV for electrons, positrons and photons
Ti5 Sample Holder Nb3Sn Cable Coolant
LHe 1.16 x 10-2 0.01% 2.65 x 10-3 0.03% 1.56 x 10-2 0.008%
LN2 1.18 x 10-2 0.01% 2.64 x 10-3 0.02% 1.54 x 10-2 0.007%
H2O 9.40 x 10-3 0.01% 2.35 x 10-3 0.02% 1.82 x 10-2 0.003%
Energy deposition (GeVpr-1)10 runs with 107 particles each
Energy Deposition
H2O
LN2
LHe
bin dimensions = 1 x 1 x 1 mm3
Energy Deposition Maps
The energy/power deposed in the sample holder is about 230 J/s (40% of the primary beam).The beam spot is larger than the sample holder
Energy Deposition MapsLHe
H2O
LN2
bin dimensions = 0.1 x 0.5 x 0.5 mm3
p beam
cable
p beam origin
Problem.
The sample moves during the critical current measurements
Solution (under discussion).
Mechanically fix the Nb3Sn sample with a Sn-Pb solderingTi5
Nb3Sn cable
Solution (only proposed) : Fix the sample with a soldering
Is it reliable ?
Solution ?
The soldering composition is 60% Sn and 40% Pb. It is, on average, similar to Cu.
30 MeV p beam
target
As from literature the range of 30 MeV protons in Cu is 1.44 g/cm2 so it is 1.6 mm being 8.96 g/cm3 the Cu density
Energy Deposition MapsLHe
H2O
LN2
bin dimensions = 0.1 x 0.5 x 0.5 mm3
p beam
cable
p beam origin
soldering
The energy deposition occurs in the soldering and not in the cable
Activation and Cooling
-500 0 500 1000 1500 2000 2500 3000 3500 40001.0x1010
1.0x1011
1.0x1012
5
10
15
20
25
Act
yvity
(B
q)
Time (s)
LHe LN2 H2O
NO WELDING
Irradiation time = 104 sProton Beam Energy = 30 MeV
Irradiation Intensity = 20 A (1.25x1014 p/s)
Activity Decay After Irradiation
Act
ivity
(C
i)
0.01 0.1 1 10 100 1000 10000 1000001.0x108
1.0x109
1.0x1010
1.0x1011
1.0x1012
0.01
0.1
1
10
Act
yvity
(B
q)
Time (s)
With soldering Without soldering
7 Days
1 Day
1 HourLHe
Irradiation time = 104 sProton Beam Energy = 30 MeV
Irradiation Intensity = 20 A (1.25x1014 p/s)
Activity Decay After Irradiation
Act
ivity
(C
i)
Questions: Can be “used” such an object ?
Are precautions needed ?
What ?
Residual NucleiTi sample holder (lower part only)
Soldering
t=0 t=1h t=7d
Temperature increase (the irradiation must not melt the cable or the sample holder)
Adiabatic Hypothesis
00032.084.04.4
230
pmc
QT Unphysical number
The specific heat at 4 K is the crucial value
The adiabatic hypothesis is not valid, so thermal conductivity and thermal exchange must be taken into account.
Thermal model has been developed (F.Liberati), but a thermal analysis is necessary, to have most reliable evaluations.
What’s Next ?
• Find mechanical solution better than the soldering
• Thermal analysis (provide the adapted USRBIN output as ANSYS input)
• Benchmarking of the simulations with the irradiation tests
• DPA evaluation (FLUKA pre-release)
