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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
EURISOL DS PROJECT
Task#2: MULTI-MW TARGET DESIGN
Adonai Herrera-Martínez & Yacine Kadion behalf of T2
European Organization for Nuclear Research, CERNCH-1211 Geneva 23, [email protected]
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Overview
1. Baseline Parameters
2. Baseline Design (BLD) vs. Hg Jet (Hg-J) → Intermediate Solution (IS)
3. Comparison of the FLUKA Simulation Results
– Primary Particle Flux → Proton Escapes
– Neutron Flux and Energy Spectra
– Fission Densities → Isotopic Yields
– Energy Deposition → Temperature Increase
4. Conclusions
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Sensitivity Study
http://eurisol-hg-target.web.cern.ch/eurisol-hg-target/
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Baseline Parameters of the MMW Hg Target
Parameter Symbol Units Nval Range
Converter Target material Zconv - Hg (liquid) LBE
Secondary Target material Ztarg - UCx, BeO
Beam particles Zbeam - Proton Deuteron
Beam particle energy Ebeam GeV 1 2
Beam current Ibeam mA 4 2 – 5
Beam time structure - - dc ac50Hz 1ms pulse
Gaussian beam geometry sbeam mm 15 25, parabolic
Beam power Pbeam MW 4 5
Converter length lconv cm 45 85
Converter radius (cylinder) rconv cm 15 8 – 20
Hg temperature Tconv ºC 150 (tbc) < 357
Hg flow rate Qconv kg/s 200 (tbc) < 3000
Hg speed Vconv m/s 2 (tbc) < 30
Hg pressure drop ΔP1 bar tbc << 100
Hg overpressure Δ P2 bar tbc << 100
UCx temperature Ttarg ºC 2000 500 – 2500
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
MMW Hg Target Configuration
• BLD: Shape of Hg target optimised for neutron production (neutron balance)
• 15 mm sigma proton beam, fully contained in the Hg target
• Possibility of further reduction in Hg target dimensions → Intermediate solution (IS)
Hg Target
Reflector
Reflector
Target container
UCx/BeO Target
Protons
73 cm
30 cmProtons
Reflector
Reflector
Hg Jet
UCx/BeO Target
UCx/BeO Target
40 cm
4 cm
• Hg-J: designed for high-energy neutron fluxes in the UnatC3 (3 g/cm3) fission target
• 4 mm sigma proton beam, mostly contained in the 4 cm diameter Hg Jet
• Use of reflector to improve neutron economy and to shield HE particles
Hg Target
Reflector
Reflector
Target container
UCx/BeO Target
Protons
68 cm
16 cm
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Primary Proton Flux Distribution
Primary flux (prim/cm2/s/MW of beam)• 1GeV proton range ~ 46 cm
• BLD: Beam fully contained inside
• Hg-J: Important HE primary escapes (~1013 prim/cm2/s/MW of beam), mostly at small polar angles (up to 25% losses)→ Beam dump
• IS: Some primary escapes through the endcap, mostly contained by the reflector
• BLD and IS: Beam window suffering ~100 μA/cm2/MW (radiation damage limit)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Neutron Flux Distribution
Neutron flux (n/cm2/s/MW of beam)
• Neutron fluxes in the fission target ~1014 n/cm2/s/MW of beam
• BDL and IS: Partial containment by the reflector of the escaping neutron flux
• Hg-J: Higher neutron flux in the fission target (~2×1014 n/cm2/s/MW of beam)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
238U Fission Cross Section
0
0.5
1
1.5
2
2.5
5 15 25 35 45 55 65 75 85 95 105
Energy (MeV)
Sigm
a (B
arn)
neutron
proton
deuteron
• Significantly harder spectrum for the Hg-J, with a peak neutron energy between 1 − 2 MeV, compared to 300 keV for BLD and 700 keV for IS
• Very low fission cross-section in 238U below 2 MeV (~10-4 barns). Optimum energy: 35 MeV
• Use of natural uranium: f in 235U (0.7% wt.): at least 2 barns
• Further gain if neutron flux is reflected (e.g. BeO)
Neutron Energy Spectrum vs Fission Cross-Section in Uranium
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Fission Density Distribution in UnatC3
Fission density (fissions/cm3/s/MW of beam)• High-energy fissions in Hg → Radioactive isotopes in Hg
•BLD: 1011 fiss/cm3/s/MW, homogenously distributed
• Hg-J: High and anisotropic fission density (~4×1011 fiss/cm3/s/MW)
• IS: 2×1011 fiss/cm3/s/MW, homogenously distributed → ~1015 fissions/s for 4 MW of beam and a 1 litre UnatC3 (3 g/cm3) fission target
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
HE Fission Density Distribution in UnatC3
•Non-homogenous HE fissions in all cases
• BLD: ~10% of the fissions are HE (>20 MeV), compared to ~20% in IS and ~40% in Hg-J
HE fission density (fissions[>20 MeV]/cm3/s/MW of beam)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
LE Fission Density Distribution in UnatC3
LE fission density (fissions[<20 MeV]/cm3/s/MW of beam)
• BLD: LE fissions account for 90% of the radial fissions
• BDL and IS: Important effect of the reflector ← More LE fissions in the outside surface of the fission target
• Hg-J: Stronger anisotropy in the LE fissions and lack of containment for LE neutrons
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
• Maximum energy deposition in the first 10 cm beyond the interaction point, in Hg
• BLD and IS, maximum power density in Hg: ~2 kW/cm3/MW of beam
• Hg-J, maximum power density in Hg: ~22 kW/cm3/MW of beam!
• Power density in the UnatC3
target: ~3 W/cm3/MW of beam in the BLD and ~5 W/cm3/MW the IS, homogenously distributed in both
• ~20 W/cm3/MW of beam UnatC3
target for the Hg-J, following the fission density distribution → Strongly anisotropic
Power Densities (1)
Power density (W/cm3/MW of beam)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Power Densities (2)
Hg
Bea
m W
indo
w
• More than one order of magnitude difference between the free surface Hg-J (~22 kW/cm3/MW) and the confined Hg targets (BLD, ~2 kW/cm3/MW)
• BDL and IS: Beam window suffering important power densities (~1 kW/cm3/MW → extra cooling plus radiation resistant material needed)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Power Densities (3)
• Increasing beam from 15
to 25 mm or taking
parabolic beam of at
least 45 mm radius →
reduce T in Hg by a
factor 2 - 2.5
• Doubling the flow rate
(~2 m/s) will reduce T
by factor 2
• → T ~ 130 - 150 ºC
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope Yields in UnatC3 Target (1)
Harder neutron spectrum for the Hg Jet → more high-energy neutron induced fissions → large increase in the symmetrical fission products
Small differences in terms of asymmetrical (low energy) fission fragments
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope Yields in the UnatC3 (1)
28-Ni (A) Baseline design Intermediate solution Hg Jet
70 1.7E+05 2.9E+06 0.9 1.6E+05 17.3
71 2.0E+05 2.3E+06 1.9 3.9E+05 11.4
72 3.4E+05 2.9E+06 2.1 7.1E+05 8.5
Ni isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
31-Ga (A) Baseline design Intermediate solution Hg Jet
73 3.7E+05 9.8E+06 1.3 4.7E+05 26.4
75 1.2E+06 2.1E+07 2.3 2.8E+06 17.3
76 2.6E+06 2.8E+07 2.4 6.2E+06 10.5
77 7.1E+06 5.1E+07 2.1 1.5E+07 7.3
78 1.2E+07 6.2E+07 1.9 2.4E+07 5.0
79 2.0E+07 1.0E+08 2.0 4.0E+07 5.1
80 1.6E+07 7.4E+07 1.5 2.5E+07 4.6
81 1.4E+07 7.7E+07 1.7 2.3E+07 5.5
Ga isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope Yields in the UnatC3 (2)
Ga isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
31-Ga(A) Baseline design Intermediate solution Hg Jet
82 7.4E+06 3.1E+07 1.8 1.3E+07 4.1
83 1.9E+06 1.6E+07 2.0 3.9E+06 8.1
84 7.3E+06 8.9E+06 1.4 1.0E+07 1.2
85 2.0E+05 2.3E+06 1.9 3.9E+05 11.2
36-Kr (A) Baseline design Intermediate solution Hg Jet
84 1.9E+06 5.4E+06 2.9 6.3E+07 33.9
85 2.1E+07 3.5E+07 1.7 9.6E+07 4.6
86 7.1E+07 1.2E+08 1.7 2.8E+08 3.9
87 3.2E+08 4.8E+08 1.5 5.0E+08 1.6
88 1.2E+09 1.8E+09 1.5 1.7E+09 1.4
89 2.3E+09 3.4E+09 1.5 2.8E+09 1.2
90 3.2E+09 4.8E+09 1.5 4.6E+09 1.5
91 2.5E+09 3.8E+09 1.5 4.6E+09 1.9
92 1.5E+09 2.4E+09 1.6 3.8E+09 2.5
Kr isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope Yields in the UnatC3 (3)
Kr isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
36-Kr (A) Baseline design Intermediate solution Hg Jet
93 5.5E+08 9.6E+08 1.7 1.8E+09 3.3
94 2.0E+08 3.8E+08 1.9 9.8E+08 5.0
95 3.4E+07 6.6E+07 1.9 2.1E+08 6.2
96 3.5E+07 5.3E+07 1.5 1.0E+08 2.9
97 1.8E+06 2.0E+06 1.2 1.2E+07 6.6
98 2.2E+06 4.0E+06 1.8 7.7E+06 3.4
100 6.8E+04 7.9E+04 1.2 2.8E+05 4.1
Sn isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD
50-Sn (A) Baseline design Intermediate solution Hg Jet
117 1.53E+09 5.82E+09 3.8 7.71E+10 50.4
118 4.21E+09 1.54E+10 3.6 1.70E+11 40.5
119 6.07E+09 2.28E+10 3.8 2.08E+11 34.2
120 1.78E+10 5.44E+10 3.1 4.63E+11 26.0
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope Yields in the UnatC3 (4)
Sn isotopic yields (Ions/cm3/s/MW of beam) and ratio over BLD50-Sn (A) Baseline design Intermediate solution Hg Jet
121 2.38E+10 6.24E+10 2.6 4.75E+11 16.3
122 5.37E+10 1.36E+11 2.5 8.74E+11 14.3
123 5.44E+10 1.37E+11 2.5 7.77E+11 12.4
124 9.74E+10 2.35E+11 2.4 1.21E+12 10.2
125 8.99E+10 1.90E+11 2.1 9.21E+11 8.3
126 1.42E+11 2.95E+11 2.1 1.18E+12 5.8
127 1.60E+11 3.07E+11 1.9 9.33E+11 3.8
128 3.36E+11 5.67E+11 1.7 1.29E+12 3.2
129 4.79E+11 7.93E+11 1.7 1.54E+12 2.4
130 9.92E+11 1.62E+12 1.6 2.42E+12 2.8
131 9.24E+11 1.55E+12 1.7 2.56E+12 2.9
132 6.43E+11 1.09E+12 1.7 1.87E+12 3.4
133 1.84E+11 3.20E+11 1.7 6.30E+11 4.3
134 3.77E+10 6.80E+10 1.8 1.61E+11 4.8
135 3.40E+09 6.99E+09 2.1 1.64E+10 6.0
136 2.03E+08 1.57E+08 0.8 1.22E+09 6.0
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Conceptual Design of the MMW Hg Target
Conclusions
• The Intermediate Solution brings us closer to the ideal performance of a Hg Jet in terms of fission density and relevant isotopic yields, additionally reducing the particle escapes and power densities in Hg
• The Hg Jet presents important technical issues regarding Hg cooling, radiation damage to the nearby structures and radiation shielding
• Need to clearly establish the beam requirements (i.e. CW vs. pulsed, beam frequency and beam shape) and fission target configuration
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
The End (... or The Beginning)
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
• 3 times more fissions with UnatC compared to UnatC3 (proportional to density)
• With 238UC less isotropic distribution and fission yield reduced by factor 3
Fission Density Distribution: UnatC vs 238UC
UnatC
238UC
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
At high masses it is characterized by the presence of three peaks corresponding to(i) the initial target nuclei, (ii) those obtained after evaporation below and (iii) those obtained after acivation above (A+1)
Three very narrow peaks corresponding to the evaporation of light nuclei such as (deuterons, tritons, 3He and a)
An intermediate zone corresponding to nuclei produced by high-energy fissions (symmetric distr.)
At higher proton energy nuclei from evaporation and multi-fragmentation (ligth nuclei) are more abundant
Residual Nuclei Distributions in Hg
1x105
1x106
1x107
1x108
1x109
1x1010
1x1011
1x1012
1x1013
0 50 100 150 200
A, mass number
1 GeV impact point
2 GeV impact point
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
At high masses it is characterized by the presence of acivation products (Pu239 !!) ==> dominates over fission !!
Three very narrow peaks corresponding to the evaporation of light nuclei such as (deuterons, tritons, 3He and ) ==> very few
An intermediate zone represented double humped distribution corresponding to nuclei produced by low-energy fissions
twice as much fission in radial position
Radioisotope yields in UCx targets
1x104
1x105
1x106
1x107
1x108
1x109
1x1010
1x1011
1x1012
1x1013
0 50 100 150 200 250
A, mass number
UnatC Radial
UnatC End cap
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
5 times less fissions with U238 overall but…
equal amount of high-energy neutron induced fissions (sym. distribution)
Radioisotope yields in UCx targets (2)
1x104
1x105
1x106
1x107
1x108
1x109
1x1010
1x1011
1x1012
1x1013
0 50 100 150 200 250
A, mass number
U238C End cap
UnatC End cap
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
Radioisotope yields in UCx targets (3)
harder neutron spectrum along the beam axis with 2 GeV protons ==> more high-energy neutron induced fissions and few evaporations
no differences radially
1x104
1x105
1x106
1x107
1x108
1x109
1x1010
1x1011
1x1012
0 50 100 150 200 250
A, mass number
1 GeV radial
2 GeV radial
1x104
1x105
1x106
1x107
1x108
1x109
1x1010
1x1011
1x1012
0 50 100 150 200 250
A, mass number
1 GeV end cap
2 GeV end cap
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EURISOL DS Progress Meeting T2-03, CEA Saclay, France 27 – 28 October, 2005
He-3 He-4 He-6 C-12 C-13 N-151x109
1x1010
1x1011
1x1012
Radioisotope yields in BeO target
aim for 2x1013 6He at/s