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95-Am-241 CAD,NEA+ EVAL-APR05 Bouland, Bernard, Rugama et al.
DIST-JAN09 20090105
----JEFF-311 MATERIAL 9543
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
*************************** JEFF-3.1.1 *************************
** **
** Original data taken from: JEFF-3.1 **
** **
******************************************************************
***************************** JEFF-3.1 *************************
** **
** Original data taken from: REVISED EVALUATION **
** **
******************************************************************
******************** JEFF-3.1: Summary ***********************
Resolved Resonance Range 0-150 eV (0. Bouland):
Thermal cross sections and lowest energy resonances are
revised.
Resolved resonance parameters of the other resonances
are recovered from the KEDAK-4 evaluation of F.Froehner
Unresolved Resonance Range 150eV-40keV:
The infinite diluted cross sections were recovered from
calculated values by E.Fort who used the FISINGA1 code.
The shelf-shieding factors must be calculated from the
tabulated average resonance parameters borrowed from JENDL3.3
Continuum Range E>40keV:
Pointwise cross sections are borrowed from JENDL3.3
Angular and secondary energy distributions are borrowed
from JENDL3.3 as well.
1-452, 1-456, 1-458, 5-18: from ENDF/B-VI.8 (20 MeV)
1-455, 5-455:(Y. Rugama) NEA/OECD 8 delayed neutron groups
Jefdoc-976:Spriggs,Campbel and Piksaikin,Prg Nucl Eng 41,223(2002)
Capture Isomeric Ratio to 242Am ground and metastable states:
New evaluation for JEFF3.1 (O.Bouland & D.Bernard)
stored in file 9-102
Variances associated to the above capture Isomeric Ratios:
New evaluation for JEFF3.1 (O.Bouland) stored in file
40-102
******************** JEFF-3.1: Details ***********************
Resolved Resonance Range 0-150 eV (0. Bouland):
-----------------------------------------------
- to be published in NSE (2006) -
With regards to the differential and integral experimen-
tal data available [1] and the French Post Iradiated Experi-
ments[2], there was a trend to increase the 2200m/s capture
cross section and the epithermal resonance integral (between
0.1 and 2eV)[3]. This was the main motivation for revising the
Resolved Resonance Parameters (RRP) set of JEFF3.0. Additional
ly the bug referenced by J.Rowlands[4] has been corrected by
restarting from the original RRP evaluation of F. Froehner made
in MLBW (ENDF sense) formalism[5].
Main steps of the RRP revision:
*Choice of the prior set of RRP = F.Froehner's parameters
*Random spin assignment of the unassigned s-wave resonances set
from statistical laws (two spins being possible J=2 or 3)
*Replacement of the unique bound level by two bound levels (one
of each spin) for fine tuning of the desired thermal cross sec
tion values
*Selection of the differential data base for revising the RRP
of the 4 four lowest energy resonances=
Total cross section vs energy:
Belanova et al.[6]
Slaughter et al.[7]
Derrien et al.[8]
Absorption cross section:
Weston et al.[9]
*Consistency of this differential data base=
Energy scale
Normalisation
Background
Deviating experimental data points
*Sequential SAMMY(M6 version) fit of the RRP of the bound
levels and first four resonances to fit the thermal capture and
fission cross section desired values and the wanted epithermal
capture resonance integral value and, meanwhile keeping
a satisfactory agreement with the consistent differential data
base.
Note: The fission widths of the whole set of RRP are kept un-
changed during the SAMMY fit except for the bound levels.
Thermal quantities at 293.6 K :
Fission x-section: 3.15b (-1.0 %)
Capture x-section: 647.04b (+5.2 %)
Fission Res. Integral: 17.31b (+7.9 %)
Capture Res. Integral: 1526.4 b (+5.6 %)
Capture Epithermal Res. Int. (0.1-2.2eV): 2912.6 b (+15.8 %)
Last column above: (JEFF3.1/JEFF3.0)*100
The 2200m/s capture cross section value of 647b is a compromise
between recent activation measurements and old differential
data as detailled below:
Fioni, Marie et al. (2001)[10]:(696+-48)b
Maidana et al.(2001) [11]:(672+-10)b"extrapolated"
Belanova et al. (1976) [ 6]: 622b
Adamchuck et al. (1955) [12]: 600b
Unresolved Resonance Range 150 eV- 40 keV :
-----------------------------------------------
Infinite diluted cross sections (E.Fort et al.):
The cross sections have been calculated using the FISINGA1
code and the following averaged parameters[13]:
R' = 9.36 Fermi
D(L=0) = (0.55+-0.05)eV
S0 = (0.94+-0.09)E-04
S1 = (2.43+-0.4)E-04
Capture width (L=0) = (43.8+-0.7) meV
Capture width (L=1) = (85 +- 7) meV
Fission width = (0.24 +- 0.05) meV
Shelf-shieding factors: must be calculated from the Unresolved
Resonance Parameters (URP) borrowed from JENDL3.3 based on
Maslov et al.[14] work (see comments at the end) and modified
by T.Nakagawa (NDC/JAERI)
T.Nakagawa comments:
Average fission cross section to be reproduced was
determined from experimental data of Yamamoto et al.[15]
and Dabbs et al.[16], and the capture cross section from
Vanpraet et al.[17] and Gayther et al.[18]
The average resonance parameters were determined with ASREP
[19] to reproduce those average cross sections.
Continuum Range E>40keV :
-----------------------------------------------
Borrowed from JENDL3.3, which was mainly based on Maslov et al.
work[14].
Recall about JENDL3.3: except for the following reactions, the
evaluated data of Maslov et al.[14] were adopted:
MT= 1 Total cross section
Data of JENDL-3.2 were adopted. They were calculated with
spherical optical model parameters determined to reproduce
the total cross section measured by Phillips and Howe [20]
V = 43.4 - 0.107*EN (MeV)
Ws= 6.95 - 0.339*EN + 0.0531*EN**2 (MeV)
Wv= 0 , Vso = 7.0 (MeV)
r = rso = 1.282 , rs = 1.29 (fm)
a = aso = 0.60 , b = 0.5 (fm)
MT= 2 Elastic scattering cross section
Calculated as (total - sum of partial cross sections)
MT=18 Fission cross section
Based on the experimental data of Hirakawa [21],
Prindre et al. [22], Aleksandrov et al. [23], Cance et al.
[24], Dabbs et al. [16], Aleksandrov et al. [25],
Vorotnikov et al.[26], Wisshak anf Kaeppeler [27].
MT=102 Capture cross section
Based on the evaluated data of Maslov et al. In the MeV
region, the cross section of direct and semi-direct process
was calculated with DSD code [28].
MF=4 Angular Distributions of Secondary Neutrons
All data were taken from the evaluation by Maslov et al. [14]
MF=5 Energy Distributions of Secondary Neutrons
All data were taken from the evaluation by Maslov et al. [14]
MF=8 Radioactive Decay Data
MT=102
Decay data were taken from ENSDF.
--------------------------------------------------------------
Capture Isomeric Ratio (IR) to 242Am ground and metastable
states: new evaluation for JEFF3.1 (O.Bouland & D.Bernard)
--------------------------------------------------------------
- to be published in NSE (2006) -
MF=9 MT=102
A 3 degrees error weighted polynomial fit was performed
between all sources of information available. Nevertheless,
the data from Wisshak et al.[21] at 30keV was disregarded.
The following experimental data set was used:
Experimental data:
==================
Authors IR Value to 242gAm energy[eV]/range
Wisshak et al.[21] 0.92+-0.06 0.01475
Shinohara et al.[22] 0.90+-0.09 thermal
Fioni et al.[10] 0.914+-0.007 thermal
Gavrilov et al.[23] 0.914+-0.081 thermal
Maidana et al.[11] 0.8955+-0.019(extrapolated) thermal
Dovbenko et al.[24] 0.89+-0.029 thermal
Harbour et al.[25] 0.899+-0.032 thermal
Bak et al.[26] 0.905+-0.109 thermal
Ihle et al.[27] 0.891+-0.09 thermal&epithermal
Shinohara et al.[22] 0.89+-0.07 epithermal
Harbour et al.[25] 0.865+-0.101 epithermal
Bak et al.[26] 0.875+-0.111 epithermal
Dovbenko et al.[24] 0.84+-0.02 300000.
Post Iradiated Experiments feedback:
====================================
Authors IR value to 242gAm energy[eV]/range
Tommasi[28] 0.85+-0.01 110000.
Bernard et al.[2] 0.86+-0.01 epithermal
Other integral data :
=====================
Author IR value to 242gAm energy[eV]/range
Los Alamos[29] 2 data points fast spectrum
Disregarded datum
=================
Author IR value to 242gAm energy[eV]/range
Wisshak et al.[21] 0.65+-0.05 30000.
Energy range below 0.022eV:
An asymptotic value equal to 0.9107 (equal to the weighted
average of the thermal data; Wisshak's point at 14.75meV inclu-
ded) was fixed for this sub-thermal energy range.
A normalisation point was chosen at 20MeV based on a Talys
calculation which used 10 discrete levels in the descrip-
tion of the 242Am excited compound nucleus level scheme[30].
Note: Fluctuations of the IR are expected in the resolved reso-
nance range. A calculation of these fluctuations by D.Bernard
is in progress at CEA-Cadarache.
--------------------------------------------------------------
Variances of the 241Am capture Isomeric Ratios (IR) to 242Am
ground and metastable states: new data for JEFF3.1
(O.Bouland)
--------------------------------------------------------------
MF=40 MT=102
The variances, here below, are tabulated only for the IR to
the ground state since IR absolute variances for metastable
and ground states are identical.
The variances are essentially supplied by the 3 degrees error
weighted polynomial fit which includes 3 components:
- the estimated variance of the fitting;
equal to the ratio of the residual sum of squares to the degree
of freedom,
- the variance resulting of the variances both on the
fitting parameters and on the choice of our fitting law,
- the Student's factor (statistical small sample
theory by S.Gosset).
At very low energy where no experimental IR data or trends are
available, the variance is arbitrarily set to the weighted
average variance of the thermal data; Wisshak's point[21] at
14.75meV included.
Above 300 keV where, again, no experimental IR data or trends
are available, the variance of the polynomial fit is combined
with the half difference between our fit normalized at 20 MeV
to the IR to 242gAm value equal to 0.75 and another possible
fit based on a normalization value of 0.5.
Since the ENDF-6 rule do not allow pointwise variance data,
the resulting pointwise variances were averaged over 11
energy groups. The relative IR variances obtained [expressed
in percent] are the following:
Energy groups RelVar(IR to 242gAm) RelVar(IR to 242mAm)
[eV] [percent] [percent]
1.E-5 to 0.022 0.69 7.05
0.022 to 0.1 0.42 3.54
0.1 to 0.45 0.49 3.38
0.45 to 0.8 0.58 3.88
0.8 to 1.6 0.64 4.06
1.6 to 2.1 0.68 4.56
2.1 to 150. 0.71 4.08
150. to 4.E+4 0.54 3.15
4.E+4 to 3.E+5 0.51 2.75
3.E+5 to 1.E+6 1.75 8.47
1.E+6 to 2.E+7 11.36 38.77
References
1/ O.Bouland, JEF/DOC-931
2/ D.Bernard et al., JEF/DOC-1043
3/ O.Bouland, JEF/DOC-1050
4/ J.Rowlands, JEFF report 17, page 235
5/ F.Froehner et al., Nucl. Data Conference, Antwerp (1982)p211
6/ T.Belanova et al., Exfor 40305.003 (1976)
7/ G.Slaughter et al., Exfor 12478.003 (1961)
8/ H.Derrien et al., 75 WASH., 2, 637 (1975) and Exfor 20415.003
9/ L.Weston and J.Todd, Nucl. Sci. Eng., 61, 356, (1976)
10/ G.Fioni, F.Marie et al., Nucl. Phys. A 693 (2001) 546
11/ N.Maidana et al., Exfor 12478.003 and J,RCA,89,419 (2001)
12/ J.Adamchuk et al., Nucl. Sci. Eng., 61, 356 (1976).
13/ E.Fort et al., Nucl. Data Conference, Knoxville (1979) 862
14/ V.Maslov et al., INDC(BLR)-5 (1996)
15/ Yamamoto S. et al., Nucl. Sci. Eng., 126, 201 (1997)
16/ J.Dabbs et al., Nucl. Sci. Eng., 83, 22 (1983)
17/ G.Vanpraet et al., 1985 Santa Fe, Vol.1, p.493 (1985)
18/ D.Gayther D.B. and B.Thomas, 1977 Kiev, Vol. 3, p.3 (1977)
19/ Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999)
20/ T.Phillips and R.Howe, Nucl. Sci. Eng., 69, 375(1979)
21/ K.Wisshak et al., Nucl. Sci. Eng., 81, 396 (1982)
22/ N.Shinohara et al., J. Nucl. Sci. Technol., 34, 7 (1997)
23/ V.Gavrilov, J. AE,41,185 (1975)
24/ A.Dovbenko et al., LA-tr-71-74 (1971)
25/ R.Harbour et al., Nucl. Sci. Eng., 50, 364 (1973)
26/ M.Bak, J. AE,23,(4),316 (1967)
27/ H.Ihle et al., J. Inorg. Nucl. Chem., 34, 2427 (1972)
28/ J.Tommasi, "Analysis of the PROFIL1 and 2 experiments...",
to be published in NSE (2006)
29/ P.Talou, private communication (2004)
30/ A.Koning, private communication (2004)
========== Comments from Maslov's Evaluation =====================
95-Am-241 MINSK BYEL EVAL-MAY96
DIST-MAY96
V.M. Maslov, E.Sh. Sukhovitskij,
Yu.V. Porodzinskij, A.B. Klepatskij,
G.B. Morogovskij
Status
Evaluation was made under the project agreement CIS-03-95
with international science and technology center (Moscow).
Financing party of the center for the project is japan.
Evaluation was requested by y.kikuchi (jaeri, tokai)
MF=2
Unresolved resonance region : 0.15 - 41.3483 keV.
energy independent parameters:
R=9.157 Fm from optical model calculations
S1=2.204E-4 from optical model calculations
S2=1.022E-4 from optical model calculations
Energy dependent parameters:
S0 - decreases from .864-4 (0.15keV)to .807-4 (41.4keV)
D - spin dependent, normalized to =0.505 eV
with account of level missing /A/
WF -spin dependent as defined by the transition state
spectra at inner and outer barrier humps,normalized
to =0.38 meV to fit unresolved resonance region
experimental fission data /B/.
WG - from cascade model with account of fission
competition,spin dependent. normalized to =
0.0484 eV.
MF=3 Neutron cross sections
MT=1,4,51-60,91,102. Total, elastic and inelastic
scattering, capture cross section
total,direct elastic and direct inelastic for mt=51,
52,53 and optical transmission coefficients from
coupled channels calculations.
The deformed optical potential used:
VR=46.15-0.3*E(MEV) RR=1.26 FM AR=0.615 FM
WD= 3.56+0.4*E(MEV) E < 10 MEV RD=1.24 FM
WD= 7.77 E => 10 MEV AD=0.5 FM
VSO=6.2 RSO=1.12 ASO=0.47 B2=0.181 B4=0.076
Four lower levels of ground state rotational band
are coupled.
Capture,compound elastic and inelastic by statistical
model, see mt=18-21
Above neutron energy 5 Mev capture is assumed to be
0.001 barn as predicted by direct and semi-direct
capture calculations
adopted level scheme of am-241 from nuclear data
sheets /C/ (9 levels) plus 1 level added for band
K,P=5/2+ according to ej=a(j(j+1)-k(k+1))
No Energy(MeV) Spin-parity K
g.s. 0.0 5/2 - 5/2
1 0.041176 7/2 - 5/2
2 0.09365 9/2 - 5/2
3 0.158 11/2 - 5/2
4 0.20588 5/2 + 5/2
5 0.234 13/2 - 5/2 *
6 0.235 7/2 + 5/2
7 0.239 3/2 - 3/2
8 0.272 9/2 + 5/2
9 0.273 5/2 - 3/2
10 0.312 15/2 - 5/2
* - ADDED
Overlapping levels are assumed above 0.312 MeV
level density parameters: see mt 18-21
MT=16,17. (n,2n) and (n,3n) cross section
From statistical model calculations /D/ with the
account of pre-equilibrium neutron emission:see mt=18-21
MT=18,19,20,21. Fission cross section is calculated within
statistical model /E/, the measured data of:
Dabbs et al./9/, Hage et al./F/, Wisshak et al./G/,
Kupriyanov et al./H/, Knitter et al. /I/,
Prindle et al./J/, Fomushkin et al./K/ are fitted.
The first chance fission mt=19 is calculated with
The contribution of emissive fission to total fission
cross section is calculated according to /D,E/.
MF=4 Angular distributions of secondary neutrons
FOR MT=2,51,52,53 from coupled channels calculations
with added isotropic statistical contribution.
MT=16,17,18,52,54-60,91,16 isotropic
MF=5 Energy distributions of secondary neutrons
Energy distributions for mt=16,17 were
calculated by statistical model of cascade neutron
emission taking into account the history of the decay
with the allowance of pre-equillibrium emission of
the first neutron /L/
Energy distributions for mt=18,19,20,21 were
calculated by madland-nix model /M/ with account for
The effects of and competition between multiple-chance
fission processes up through third-chance fission
with the allowance of pre-equillibrium emission of
the first neutron /L/
REFERENCES
A. Porodzinskij Yu.V.,Sukhovitskij E.Sh., Nuclear Constants,
4, 27,1987.
B. Dabbs J.W.T. et al., Nucl. Sci. Eng., 83, 22, (1983).
C. ENDSF, 1995
D. Ignatjuk A.V., Maslov V.M., Pashchenko A.B. Sov. J. Nucl.
Phys. 47, 224 (1988).
E. Maslov V.M. et al. INDC(BLR)-003, 1996
F. Hage W. et al. Nucl. Sci. Eng., 78, 248 (1981).
G. Wisshak K. et al. Nucl. Sci. Eng., 76, 148 (1980).
H. Kupriyanov S. et al. Sov. J. At. Energy, 45, 176, 1979
I. Knitter et al. Atomkernenergie, Kerntechnik,3,205, 1979
J. Prindle et al., Phys.Rev. C20, 1824, 1979
K. Fomushkin E.F.et al. Sov. J. Nucl. Phys.5, 689, 1967
L. Maslov V.M., Porodzinskij Yu.V.,Sukhovitskij E.Sh., Proc.
Int. Conf. on Neutron Physics, 14-18 Sept., Kiev, USSR,
v.1, p.413, 1988.
M. Madland D.G., Nix J.R., Nucl. Sci. Eng., 81, 213, (1982).
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