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Modernizing the Fission Basis: Measurement of Fission Product Yields from Fast-Neutron-Induced Fission. TUNL Seminar. September 12, 2013. Anton Tonchev for the LLNL-LANL- TUNL collaboration. 622876. Acknowledgements. TUNL Duke C . BHATIA M. BHIKE B. FALLIN C. HOWELL W. TORNOW - PowerPoint PPT Presentation
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Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx1
LLNL-PRES-XXXXXXThis work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract
DE-AC52-07NA27344. Lawrence Livermore National Security, LLC
Modernizing the Fission Basis: Measurement of Fission Product Yields from Fast-Neutron-Induced FissionTUNL Seminar
Anton Tonchev for the LLNL-LANL-TUNL collaboration
September 12, 2013
622876
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx22
TUNLDukeC. BHATIAM. BHIKEB. FALLINC. HOWELLW. TORNOW N.C. State Univ.M. GOODENJ. KELLEY
LLNLJ. BECKERR. HENDERSONJ. KENNEALLYR. MACRIC. RYANS. SHEETSM. STOYERA. TONCHEV
LANLC. ARNOLDE. BONDT. BREDEWEGM. FOWLERW. MOODYR. RUNDBERGG. RUSEVD. VIEIRAJ. WILHEMY
Acknowledgements
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx3
Outline
1. Motivation
2. Energy Dependence of Fission-Product Yields
3. Experimental technique
4. Results
5. Future plans
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx4
Motivation
Resolve the long-standing difference between LLNL and LANL with respect to selected fission product data
Joint LANL/LLNL fission product review panel endorsed a possible energy dependence of 239Pu(n,f)147Nd fission product yield with fission neutrons:
4.7%/MeV from 0.2 to 1.9 MeV (M. Chadwick)
3.2%/MeV from 0.2 to 1.9 MeV (I. Thompson)
Mostly low energy data from critical assembly or fast reactors
239Pu(n,f)147Nd
M.B. Chadwick et al. Nuclear Data Sheets 111 (2010) 2923; H.D Selby et al. Nuclear Data Sheets 111 (2010) 2891.P. Baisden et al, LLNL-TR-426165, 2010; R. Henderson et al. LLNL-TR-418425-DRAFT; I. Tompson et al. Nucl. Sci. Eng. 171, 85 (2012)
There are no 147Nd data between 1.9 and 14 MeV
Very scarce experimental data at the MeV-range
Large discrepancy (~20%) at 14 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx5
Nuclear Fission
Scissionpoint
0
10-17
85% KE10-20 10-15
Prompt n-emission
10-18
10-15
10-12
Prompt g-emission
Beta decay,
delayed n,g
10-6
10-9
Credit: Encyclopædia Britannica, Inc
Saddlepoint
Distance betw
een fragments (cm
)
time (s)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx6
Mass DistributionP
re-a
ctin
ides
((e.
g.W
,Au,
Pb,
Bi)
Hea
vy(E
s to
Lr)
M
ediu
m(U
to C
f)
Asymmetric
Symmetric
Symmetric
Lig
ht(T
h, P
a )
Triple humped
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx7
Fission Fragment Distribution with Neutron Energy
YiE (A) = fractional yields of mass chain ‘A’ (after b decays) from initial
actinide ‘i’ for neutron energy ‘E’.
How does the asymmetry evolve with neutron energy for 235,238U, 239Pu?
Depends on actinide Depends on neutron energy
Goal: Develop high-precision FPY energy dependence from 1 to 15 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx8
Monoenergetic Neutron Sources available at TUNLDD, DT, PT, and PLi, Sources
DENIS source FN TANDEM 10MV
Shielded neutron source area
Flux on target (107 - 108) cm-2 s-1
Energy spread dE/E = 0.1 to 0.402H(d,n)3He; Monoenergetic neutrons: 4.0 – 7.7 MeV
3H(p,n)3He; Monoenergetic neutrons: 0.5 – 7.7 MeV
Quasi-monoenergetic neutrons
7Li(p,n)7Be; Monoenergetic neutrons: 0.1 – 0.65 MeV
3H(d,n)4He; Monoenergetic neutrons: 14.8 – 20.5 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx9
TUNL TOF Room
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx10
2H gas
From VdG accelerator
p or dn
One thick target ~0.2 g/cm2
Two thin targets ~10 μg/cm2
Dual fission chamber n-detector
Monoenergetic Neutron Irradiation
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx11
Dual Fission Chamber Measurements
Fission_counts = mf F σn,f εf tf
Gamma_counts (147Nd) = mγ F σn,f FPY Iγ εγ tγ
mγ ( mf) = atoms in the 239Pu thick (thin) target F = neutron flux (n.cm-2.s-1)
σn,f = 239Pu(n,f) fission cross section (cm2) FPY = fission product yield of 147Nd per 239Pu fission
Iγ = branching ratio of Eg εγ (εf) = counter efficiency of g-ray (fission) detection
tγ ( tf) = time factor for irradiation and counting periods of g-ray (fission)
(Gamma_count / Fission_count) = (mthick / mthin) * FPY * C
FPY = (Gamma_count) / Fission_count) * (mthin / mthick) * C
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx12
Error estimation on the FPY Measurements:
Relative FPY Ratio (This is what we have promised)
1. Statistical uncertainties of g-ray peak counts (1-2%)2. Relative HPGe detector efficiency (1-2% including the fit)
Absolute FPY energy dependency:
1. Statistical error of g-ray peak counts (1-3%)2. Absolute detector efficiency (2% including the fit)3. Branching ratios (0.2 – 8% (147Nd))4. Absolute FC efficiency (3% experimentally, 0.5% simulation)5. Low energy neutrons (<1%)6. Neutron fluence rate fluctuation (<0.3%)7. Efficiency conversion ratio between close and standard geometry (<1%)8. True coincidence summing (<1%)9. Random coincidence summing (<0.2%)10. Sample weight (<0.1%)11. Self-absorption of g-ray (0.1 - 1%)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx13
Need to know?
Room returns neutrons – at ToF area
ToF spectrum from neutron and 3He monitors
Fission chamber design and characteristics
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx14
Room Return Neutrons: Why are they Important?
Region of interest
Not desirable events in our measurements
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx15
Room return neutron study with 16 different off-axis foils in ToF area
Reactions studied115In(n, n')115mIn197Au(n, 2n)196Au27Al(n, a)24Na235U (n, f) 133I and 135I
Room return neutrons ~ 105 times smaller than primary flux on target
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx16
Need to know?
Room returns neutrons – at ToF area
ToF spectrum from neutron and 3He monitors
Fission chamber design and characteristics
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx17
ToF spectrum from 0-degree neutron monitor at En=9.0 MeV
Neutron and gamma are well separated
Break up – Negligible
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx18
Need to know?
Room returns neutrons – at ToF area
ToF spectrum from neutron and 3He monitors
Fission chamber design and characteristics
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx19
Dual Fission Chamber: The Renaissance of the NIST idea
Design and fabricate three fission chambers: one for 239Pu, one for 235U, and one for 238U
Dedicated thin (~10 μg/cm2) 235,238U and 239Pu foils electroplated on 0.5” titanium backing★
Dedicated thick (200 - 400 mg/cm2) 235U (93.27%) 238U (99.97%) and 239Pu (98.4%) targets
Fission chamber efficiency confirmed: 100%, confirmed with activation measurements
★ Made by LANL
Gas flow in and out
FC gas cell
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx20
Fission Spectrum at En = 9.0 MeV
Excellent a / fission separation
alpha
fission
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx21
Fission Chamber TOF at En = 9.0 MeV
in cadmium
without cadmium
9 MeV / Background neutrons = 150 / 1
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx22
Experimental Results
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx23
FPY Ratios to 99Mo for 239Pu at 4.6, 9.0, 14.5, and 14.8 MeV
FP/ 99Mo
Present
Data
Present
Data
Present
Data
Present
Data
Gindler 1
et al.
LANL2
Selby et al.
Saclay3
J. Laurec et al.
England 4 et al.
LANL5 LLNL6
Nethaway
<Einc> 4.6 MeV 9 MeV 14.5 MeV 14.8 MeV 4.5 MeV 1.3 -1.5 MeV 14.7 MeV 14 MeV 14 MeV 14.8 MeV
87Kr91Sr92Sr97Zr
105Ru131I
132Te133I
140Ba142La143Ce147Nd
0.21 ± 5.3%0.52 ± 2.2%0.56 ± 4.3%0.96 ± 3.3%0.96 ± 3.7%
-0.83 ± 5.2%1.18 ± 5.0%0.89 ± 3.8%
-0.63 ± 3.9%0.37 ± 5.1%
0.22 ± 5.3%0.48 ± 1.4%0.51 ± 3.7%0.89 ± 2.9%0.85 ± 2.2%0.93 ± 3.3%0.76 ± 4.0%1.03 ± 3.5%0.82 ± 3.0%0.80 ± 2.1%0.64 ± 2.6%0.34 ± 3.9%
0.22 ± 5.5%0.52 ± 1.4%0.52 ± 3.7%0.97 ± 2.1%0.86 ± 2.0%1.03 ± 3.0%0.80 ± 4.0%1.09 ± 3.9%0.84 ± 2.3%0.85 ± 2.0%0.64 ± 2.3%0.35 ± 3.2%
0.21 ± 5.3%0.53 ± 1.8%0.52 ± 3.8%0.86 ± 2.7%0.86 ± 2.7%
-0.76 ± 4.9%0.88 ± 3.7%0.85 ± 2.8%0.90 ± 3.4%
-0.36 ± 4.6%
0.22 ± 4.5%0.51 ± 4.8%0.58 ± 6.4%0.93 ± 0.6%0.87 ± 6.0%
-0.84 ± 0.7%1.11 ± 0.6%0.88 ± 0.6%0.79 ± 5.9%0.65 ± 0.6%
-
0.77 ± 4.5%
----
0.85 ± 4.2%
-0.71 ± 5.2%
0.34 ± 3.5%
---
0.83 ± 3.3%-
0.61 ± 3.5%0.81 ± 4.5%0.99 ± 6.2%0.82 ± 3.1%
-0.67 ± 3.2%0.31 ± 5.2%
--
0.93 -
0.920.700.940.78
-0.590.36
0.86 ± 7.1 %0.74 ± 6.0 %0.97 ± 5.2 %0.61 ± 7.9 %0.74 ± 5.7 %0.74 ± 5.8 %
-0.34 ± 6.3 %
0.86 ± 7.1 %--
0.6 ± 7.1%-
0.72 ± 7.1 %
-0.33 ± 7.1 %
1 J.E.Gindler et al. Phys. Rev. C 27 (1983) 2058.2 H.D.Selby et al. Nucl. Data Sheets 111(2010)2891-2922.3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980.4 T.R. England and B.F. Rider, LA-UR-94-3106.5 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–31526 D.R.Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx24
FPY Ratios to 99Mo for 235U and 238U at 4.6, 9.0, and 14.5 MeV
FP/ 99Mo PresentData
PresentData
Present
DataGlendenin et al. 1
ANLSelby et al. 2
LANLLaurec et al. 3
SaclayMaeck mass-spectrometry4
England et al.5
Innes et al. 6
LANLNethaway et
al.7
LLNL
<Einc> 4.6 MeV 9 MeV 14.5 MeV 3.9 MeV ~1.4 MeV 14.7 MeV 0.2-0.4 MeV 14 MeV 14 MeV 14.8 MeV238U
97Zr105Rh
131I132Te135Xe140Ba141Ce143Ce147Nd
0.86 ± 2.6 %0.55 ± 3.0 %
-0.74 ± 4.3 %
-0.79 ± 2.9 %
-0.70 ± 3.2 %0.35 ± 3.5 %
0.85 ± 2.4 %0.62 ± 3.3 %0.60 ± 2.7 %0.74 ± 4.5 %
-0.87 ± 2.8 %
-0.73 ± 3.1 %0.37 ± 2.8 %
0.97 ± 2.2 % 0.76 ± 3.4 %0.71 ± 2.2 %1.18 ± 5.4 %1.15 ± 3.4 % 0.93 ± 2.5 %0.88 ± 2.4 %0.87 ± 2.6 %0.40 ± 3.5 %
0.94 ± 0.2 %0.73 ± 0.4 %0.56 ± 0.2 %0.82 ± 0.3 %
-1.03 ± 0.5 %
-0.77 ± 0.4 %0.45 ± 0.4 %
----
0.92 ± 3.6 %--
0.42 ± 3.8 %
0.89 ± 3.4 %0.58 ± 5.0 %0.70 ± 3.4 %0.81 ± 4.7 %0.99 ± 4.8 %0.79 ± 3.3 %0.67 ± 3.5 %0.77 ± 3.2 %0.34 ± 5.4 %
-----
0.95 ± 2.4 %--
0.40 ± 1.8 %
0.930.570.690.811.020.880.530.700.37
0.89 ± 6.1 %0.57 ± 14.7 %0.71 ± 5.6 %0.82 ± 5.9 %
-0.80 ± 5.9 %
0.75 ± 5.9 % -
0.37 ± 5.6 %
0.88 ± 6.5 %----
0.78 ± 7.2 %-
0.86 ± 7.2 % 0.36 ± 7.0 %
235U 97Zr
105Rh131I
132Te140Ba143Ce147Nd
1.04 ± 4.4 %0.37 ± 2.5 %
-1.09 ± 4.6 %0.99 ± 3.6 %0.93 ± 3.8 %0.35 ± 4.3 %
1.04 ± 2.4 %0.39 ± 2.4 %0.91 ± 3.6 %1.08 ± 4.2 %1.05 ± 2.9 %0.93 ± 3.8 %0.30 ± 3.0 %
1.02 ± 1.8 %0.37 ± 1.8 %0.84 ± 2.4 %1.10 ± 3.3 %1.06 ± 2.5 %0.92 ± 2.6 %0.38 ± 2.7 %
1.09 ± 0.4 %-
0.73 ± 0.3 %0.94 ± 0.4 %1.07 ± 0.4 %0.86 ± 0.5 %0.41 ± 0.3 %
----
0.97 ± 3.3 %-
0.36 ± 3.4 %
0.98 ± 3.6 %-
0.86 ± 3.3 %0.81 ± 4.7 %0.89 ± 3.3 %0.72 ± 3.3 %0.30 ± 5.5 %
----
1.01 ± 1.4 %-
0.34 ± 1.4 %
1.010.360.800.790.880.740.32
0.99 ± 6.6 %0.37 ± 6.0 %0.89 ± 5.8 %0.81 ± 5.5 %0.89 ± 5.5 %
-0.32 ± 5.8 %
1 ± 13.9 %---
0.83 ± 10.6 %-
0.32 ± 11.9 %
1 L. E. Glendenin et al. Phys. Rev. C 24 (1981) 2600.2 H. D. Selby et al. Nucl. Data Sheets 111(2010)2891-2922.3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980.4 W.J. Maeck et al., ENICO – 1028 (1980).5 T.R. England and B.F. Rider, LA-UR-94-3106.6 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–3152.7 D. R. Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827.
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx25
239Pu FPY Ratios to 99Mo: at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary
90 100 110 120 130 140 1500.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6 239Pu_TUNL
147Nd143Ce
140Ba
133I
132Te
131I97Zr
Mass Number of fission fragments
Yie
ld r
atio
( X
/ 9
9 Mo
) TUNL_4.6MeV TUNL_9MeV TUNL_14.5 MeV TUNL_14.8 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx26
235U FPY Ratios with Respect to 99Mo: Comparison Preliminary
90 100 110 120 130 140 1500.0
0.5
1.0
1.5
2.0
147Nd
143Ce
140Ba132Te
131I
105Rh
97Zr
235U Y
ield
rat
io (
X /
99 M
o )
Mass Number of fission fragments
TUNL_9 MeV LA-UR-94-3106_14MeV Saclay_14.7 MeV LANL_1.3-1.5 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx27
238U FPY Ratios with Respect to 99Mo: Comparison Preliminary
90 100 110 120 130 140 1500.0
0.5
1.0
1.5
147Nd
143Ce
140Ba132Te
131I
105Rh
97Zr
238UY
ield
rat
io (
X /
99 M
o )
Mass Number of fission fragments
TUNL_9 MeV LA-UR-94-3106_14MeV Saclay_14.7 MeV LANL_1.3-1.5 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx28
239Pu FPY Ratios: 147Nd/99Mo at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary
0 2 4 6 8 10 12 14 160.20
0.25
0.30
0.35
0.40
0.45
0.50
En (MeV)
FPY COMPARISON_239Pu14
7 Nd
/ 99M
o
TUNL Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx29
239Pu FPY Ratios: 140Ba/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary
0 2 4 6 8 10 12 14 160.0
0.2
0.4
0.6
0.8
1.0
1.2
En (MeV)
FPY COMPARISON_239Pu14
0 Ba
/ 99M
o
TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx30
239Pu FPY Ratios: 97Zr/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary
0 2 4 6 8 10 12 14 160.0
0.2
0.4
0.6
0.8
1.0
1.2
En (MeV)
FPY COMPARISON_239Pu97
Zr
/ 99M
o
TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx31
147Nd Absolute Fission Product Yield Preliminary
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx32
147Nd Absolute Fission Product Yield Preliminary
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx33
147Nd Absolute Fission Product Yield Preliminary
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx34
Comparison with Theory
1. Our absolute magnitude of the 147Nd FPY below 2.5 MeV and at 14.5 MeV neutron energies are slightly higher than the predicted values.
2. We can rule out the two low-yield data at 14.8 MeV.
3. The slope of 147Nd FPY from 4.6 to 14.8 MeV is slightly negative (-1% / MeV).
4. There is no energy dependence (or it is below our experimental sensitivity) for 140Ba and 99Mofragments.
Model calculation ___Uncertainties ___
J. Lestone. Nuclear Data Sheets 112 (2011) 3120
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx35
SummaryWe start delivering precise (< 2% relative uncertainty) information on FPY ratios obtained at SIX energies in case of 239Pu and at FOUR energies for 235U and 238U
We will deliver accurate (4-5% absolute uncertainty) information on the energy dependent fission product yields covering an energy range from 1 < En < 15 MeV
Potential experiments:
Reduce 147Nd branching ratio uncertainty from the current 8%
High-accuracy measurements in the 0-2 MeV range to clarify 144Ce and 147Nd neutron-energy dependence
Strong LLNL-LANL-TUNL Collaborative Effort
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx36
Additional Slides
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx37
Further Experiment & Theory NeededFuture experiments (2013 – 2015):
Reduce 147Nd branching ratio uncertainty from the current 8% (submitted LLNL LDRD proposal)
Developing a high-intensive 7Li(p,n) neutron source at TUNL
High-accuracy measurements in the 0-2 MeV range to clarify 147Nd neutron-energy dependence using 7Li(p,n) and 3H(p,n) reactions
Two measurements at the both sides of the 2nd chance fission, i.e. En = 5 and 7 MeV
Thermal measurement at the MIT reactor
Potential theory work:
Guidance on shape from onset of 2nd-chance fission
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx38
Summary of identified fragments for 235U, 238U and 239Pu
Fragment Eg (keV)' T1/2 Ig %
95Zr 756.725 12 64.032 d 6 54.38 % 2297Zr 743.36 3 16.749 h 8 93.09 % 16
105Rh 318.9 1 35.36 h 6 19.1 % 6127Sb 685.7 5 3.85 d 5 36.8 % 2
131I 364.489 5 8.0252 d 6 81.5 % 5132I 954.55 9 1.387 h 15 17.6 % 5
132Te 228.16 6 3.204 d 13 88 % 3133I 529.872 3 20.83 h 8 87.0 % 23
135Xe 249.794 15 9.14 h 2 90 % 3140Ba 537.261 9 12.7527 d 23 24.39 % 22141Ce 145.443 34 32.508 d 1 48.29 % 20143Ce 293.266 2 33.039 h 6 42.8 % 4147Nd 531.016 22 10.98 d 1 13.37 % 11
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx39
Extra Slides
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx40
Extra Slides
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx41
239Pu FPY Ratios: 147Nd/99Mo at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx42
239Pu FPY Ratios: 147Nd/140Ba at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx43
239Pu Fission chamber spectra at En = 14.5 MeV
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx44
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx45
239Pu FPY Ratios: 132Te/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary
0 2 4 6 8 10 12 14 160.0
0.2
0.4
0.6
0.8
1.0
1.2
En (MeV)
FPY COMPARISON_239Pu
132 T
e / 99
Mo
TUNL Gindler_ANL(1983) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx46
239Pu FPY Ratios: 143Ce/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary
0 2 4 6 8 10 12 14 160.0
0.2
0.4
0.6
0.8
1.0
En (MeV)
FPY COMPARISON_239Pu14
3 Ce
/ 99M
o
TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994)
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx47
What We Have Done so Far
1. Precise FPY measurements on 239Pu, 235U and 238U En = 1.5, 2.6, 4.6, 9.0, 14.5, and 14.8 MeV
2. From September 2011 to April 2013:
Total beam on target ~ 1000 hours
Funded by NNSA AA (Multiply by ~$300 / h)
3. Counting time at TUNL: more than a year of continuous fission products measurement
Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx48
Reducing fission-product g-ray branching-ratio uncertainties
147CeQb=3.4 MeV
56.4 sIY: 1.91%
147PrQb=2.7 MeV
13.4 mIY: 0.18%
147NdQb=0.9 MeV
10.98 dIY: 0.001%
b-
b-
b-
Produce pure sources using mass-separated CARIBU fission-product beam…
(DM/M~10-4… only need DM/M~10-2)(1010 atoms after 1 day)
…collaborate with TAMU for high-precision b and g-ray spectroscopy
At TAMU, they have a unique HPGe detector laboriously calibrated to ~0.2% for efficiency
count b decays with low-threshold 4p b counter (~100% efficient for bs)
N. Scielzo: ER-LDRD proposal