EVALUATION OF 236U NUCLEAR DECAY DATA

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Transcript EVALUATION OF 236U NUCLEAR DECAY DATA 

EVALUATION OF 236U NUCLEAR
DECAY DATA
Aurelian Luca
“Horia Hulubei” National Institute of Physics and
Nuclear Engineering (IFIN-HH), Radioisotope
Production Dept., Radionuclide Metrology
Laboratory, Magurele, Romania
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
1
Introduction
•
The evaluation of 236U nuclear decay data
was performed in the frame of the IAEA
Research contract no. 13341/2005 (“Improved
decay data for important actinides”), within the
IAEA CRP “Updated Decay Data Library for
Actinides”, according to the DDEP procedures.
• 236U: alpha-gamma radiations emitter, with weak
spontaneous fission (9.410-8 % branch) and
very weak cluster decay – Ne and Mg emission
(~10-13 probability relative to alpha decay,
according to Tretyakova et al., 1994).
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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References (selection)
•
•
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•
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K.F. Flynn, A.H. Jaffey, W.C. Bentley and A.M. Essling, “Precision
Measurement of Half-Life and Specific Activity of 236U”, J. Inorg. Nucl.
Chem. 34, 1121-1129, 1972
A. Rytz, “New Catalogue of Recommended Alpha Energy and Intensity
Values”, At. Data Nucl. Data Tables 23, 507-533, 1979.
W.B. Ewbank, Y.A. Ellis and M.R. Schmorak, “Spontaneous Fission
Activities”, Nuclear Data Sheets 26, 1-3, 1979.
M.R. Schmorak, “Nuclear Data Sheets for A=232, 236”, Nuclear Data
Sheets 36, 367-427, 1982 and Nuclear Data Sheets 63, 139-215, 1991
S.N. Belenky, M.D. Skorokhvatov and A.V. Etenko, “Measurement of the
Characteristics of Spontaneous Fission of 238U and 236U”, Sov. At. Energy
55, 528-531, 1983.
“Decay Data of the Transactinium Nuclides”, Technical Reports Series no.
261, IAEA, Vienna, 1986, A. Lorenz, p. 157,163, 168.
R.J. Gehrke, J.D. Baker and C.L. Riddle, “Feeding of the 232Th levels from
the decay of 236U”, Appl. Radiat. Isot. 56, 567-568, 2002.
G. Audi, A.H. Wapstra and C. Thibault, "The Ame2003 atomic mass
evaluation (II)",
Nuclear Physics A729, 337-676, 2003.
E. Browne, “Nuclear Data Sheets for A=232”, Nuclear Data Sheets 107,
2579, 2006
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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236U
Nuclear Decay Scheme (Isotope Explorer v.2.23/1999)
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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Evaluation Tools (software)
• SAISINUC 2000, version 2006-fevrier, 2/16/2006
[Laboratoire National “Henri Becquerel”(LNHB),
CEA, BNM, France]
• Lweight4 for Excel (C. Dulieu, LNHB), based on
LWeight (D. MacMahon, E. Browne)
• ICC2005 (LNHB, CEA, BNM, France)
• BrIcc v.2.0 (T. Kibedi et al., 2005)
• EMISSION v.3.03, 2001 (PTB, Germany)
• Nuclear Science References (NSR) database,
NNDC/BNL, USA (http://www.nndc.bnl.gov/nsr/)
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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Half-life Evaluation
Crt. Half-life and
No. uncertainty
(/107 years)
Reference
1.
2.46(14)
Jaffey et al., 1951
2.
2.391(57)
Fleming et al., 1952
3.
2.3415(39)
Flynn et al., 1972
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
Evaluated
value
(/107 years)
2.371(37)
6
Spontaneous Fission Half-life Evaluation
Crt. S.F. Half-life &
No.
uncertainty
(/1016 years)
Reference
1.
2.0(16)
Jaffey and Hirsch
(1949)
2.
2.7(3)
Conde and
Holmberg (1971)
3.
2.43(13)
von Gunten et al.
(1981)
4.
2.7(4)
Belenky et al.
(1983)
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
Evaluated
value
(/1016 years)
2.56(17)
7
Alpha Emissions, Normalization, Other
Details
• The spin, parity and energy levels, alpha and gamma-ray
transitions energies, alpha intensities, are adopted from
the recent evaluation of E. Browne (2006); the relative ray emission intensities are from the measured values of
Gehrke et al., 2002.
• The alpha energy, intensity and their uncertainty values
are: 4168 keV [0.000 001 42 (48)], 4332 (8) keV
[0.001 49 (22)], 4445 (5) keV [0.261 (40)]; the resulting
intensity of the main emission [4494 (3) keV] is 0.738
(40).
• Normalization for the 232Th ground state:
I ( 0 )  I (  ce)10  I ( 0 )  (1  10 )  I ( )10  100%
(100 73.8)%
I ( )10 
 0.081%
1  324.4
DDEP-2008 Workshop, 2008,
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Gamma-ray Emission Intensities
Energy / keV
Data
Uncertainty
49.46
0.10
112.79
0.10
171.15
0.20
Emission intensity and uncertainty
Relative / %
Absolute (gammas/decay)
100
0.000 81  0.000 12
24.1  0.1
0.000 195  0.000 032
0.080  0.024 0.000 000 65  0.000 000 22
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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Internal Conversion Coefficients (ICC)
• The most important case: 49.46 keV gamma-ray transitions
Shell
Total
K
L1
L2
L3
L-total
M-total
N-total
O-total
P-total
Q-total
Internal
conversion
coefficient
BrIcc
3.244102
3.989100
1.242102
1.093102
2.375102
6.499101
1.739101
3.865100
6.37110-1
1.70510-3
Internal conversion
coefficient ICC2005
(with hole hypothesis, WH)
Internal conversion coefficient
ICC2005
(without hole hypothesis, W/H)
3.244102
3.989100
1.242102
1.093102
2.375102
6.499101
1.739101
3.865100
6.37210-1
1.70610-3
3.240102
3.977100
1.239102
1.093102
2.372102
6.494101
1.738101
3.864100
6.37210-1
1.70610-3
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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Internal Conversion Coefficients (ICC) cont.
• The weak conversion case: 171.15 keV gamma-ray transitions
Shell
Total
K
L1
L2
L3
L-total
M-total
N-total
O-total
P-total
Q-total
Internal
conversion
coefficient
BrIcc
1.187100
2.04310-1
4.91310-2
4.31210-1
2.38710-1
7.19010-1
1.96710-1
5.27110-2
1.18010-2
1.98210-3
1.85510-5
Internal conversion
coefficient ICC2005
(with hole hypothesis, WH)
Internal conversion coefficient
ICC2005
(without hole hypothesis, W/H)
1.186100
2.04310-1
4.91410-2
4.31210-1
2.38710-1
7.19010-1
1.96710-1
5.27110-2
1.18010-2
1.98210-3
1.85510-5
1.180100
1.98810-1
4.87710-2
4.30710-1
2.38610-1
7.18110-1
1.96610-1
5.27010-2
1.18010-2
1.98210-3
1.85510-5
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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X-rays Energy and Intensity Values
X-rays
assignment
Th Ll
Th L
Th L
Th L
Th L
Th L total
Th K3
Th K2
Th K1
Th K3 +
Th K1 +
Th K5
Th K2 +
Th K4 +
Th KO2,3
E / keV
11.118
12.809 and
12.968
14.511
14.97,
15.605,
15.641,
16.202,
16.209,
16.426
18.98,
19.304,
19.505,
19.599
From
11.118 to
19.599
89.178
89.954
93.351
104.819 +
105.604 +
106.239
108.509 +
108.955 +
109.442
Table of Isotopes,
http://isotopes.lbl.gov/education/
Intensity and Uncertainty
Present evaluation
0.00202(20)
0.0345(18)
Intensity and
Uncertainty
0.00194(26)
0.032(4)
0.00096(10)
0.048(4)
0.00108(17)
0.047(6)
0.0106(9)
0.0111(14)
0.096(4)
0.094(10)
3.6(4) 10-8
1.20(13) 10-5
1.96(21) 10-5
7.2(6) 10-6
1.28(22) 10-5
2.1(4) 10-5
7.4(13)10-6
2.35(20) 10-6
2.5(5)10-6
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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CONCLUSIONS
• The evaluation of 236U nuclear decay data was
performed in the frame of the IAEA Research Project
no.13341/2005, according to the DDEP procedures and
by using several evaluation tools.
• The normalization condition applied to the 232Th ground
state, lead to the absolute intensity value of the main
gamma-ray emission of 49.46 keV.
• An excellent agreement was obtained in computing the
ICC values with the BrIcc v.2.0a and ICC2005 (with hole
hypothesis) software.
• The X-rays intensity values are in good agreement with
the values from TOI, but have higher uncertainties; a
future comparison with experimental values would be
very useful.
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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Acknowledgements
Thanks are due to:
• IAEA and Dr. Mark A. Kellett (Project Officer)
• Dr. Marie-Martine Be
• Dr. Valery P. Chechev
• Dr. Filip G. Kondev
• Dr. Edgardo Browne
• U.S. Department of Energy (for using Isotope
Explorer)
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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THANK YOU !
DDEP-2008 Workshop, 2008,
May 12-14, Bucharest, Romania
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