58-Ce-142
58-Ce-142 JAEA EVAL-FEB10 S.Kunieda, A.Ichihara, K.Shibata+
DIST-MAY10 20100223
----JENDL-4.0 MATERIAL 5843
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
10-02 Re-evaluation was performed for JENDL-4
(compiled by S. Kunieda).
MF= 1 General information
MT=451 Descriptive data and directory
MF= 2 Resonance parameters
MT=151 Resolved and unresolved resonance parameters
- Resolved resonance region (MLBW formula): below 15 keV
For JENDL-3, resonance parameters were evaluated by taking
into account the experimental data by Ohkubo et al./1/
They obtained reduced neutron widths of resonances in the
energy range from 1.277 to 54.9 keV. P-wave resonances found
below 12 keV were ignored because their neutron widths were
unknown. The upper boundary of resolved resonance region was
determined to be 26 keV as a result of stair-case plotting.
Average radiation width of 0.08 eV was estimated from Fig.
9 in Ref./2/ and the systematics curve by Benzi and
Reffo/3/. Scattering radius of 5.9 fm was adopted from
the compilation by Mughabghab et al./2/
Neutron orbital angular momentum L of some resonances was
estimated with a method of Bollinger and Thomas/4/.
A negative resonance was added so as to reproduce the
thermal capture cross section of 0.95+-0.05 barn recommended
by Mughabghab et al./2/
For JENDL-4.0, p-wave resonances measured by Ohkubo et
al./1/ below 12 keV were adopted by assuming S1=0.13E-4
and D1=0.56 eV. Parameters of a negative resonance were
adjusted to the elastic scattering cross section of
2.85+-0.11 b/5/ and the capture of 0.961+-0.075 b
(average of experimental data/6,7/), and shape of
the total cross section below 1 keV/1/. The upper
boundary of the resolved resonance region was set at 15 keV.
- Unresolved resonance region: 40 eV - 200 keV
The parameters were obtained by fitting to the total and
capture cross sections calculated by the POD code /8/.
The ASREP code /9/ was employed in this evaluation.
The unresolved parameters should be used only for
self-shielding calculation.
Thermal cross sections & resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 3.81281E+00
Elastic 2.85162E+00
n,gamma 9.61195E-01 8.92041E-01
----------------------------------------------------------
(*) Integrated from 0.5 eV to 10 MeV.
MF= 3 Neutron cross sections
MT= 1 Total cross section
Sum of partial cross sections.
MT= 2 Elastic scattering cross section
The OPTMAN /10/ & POD calculations /8/.
MT= 3 Non-elastic cross section
Sum of partial non-elastic cross sections.
MT= 4,51-91 (n,n') cross section
The OPTMAN /10/ & POD calculations /8/.
MT= 16 (n,2n) cross section
MT= 17 (n,3n) cross section
MT= 22 (n,na) cross section
MT= 28 (n,np) cross section
MT= 32 (n,nd) cross section
MT=102 Capture cross section
MT=103 (n,p) cross section
MT=104 (n,d) cross section
MT=105 (n,t) cross section
MT=106 (n,He3) cross section
MT=107 (n,a) cross section
Calculated by the POD code /8/.
MT=203 (n,xp) cross section
Sum of (n,np) and (n,p)
MT=204 (n,xd) cross section
Sum of (n,nd) and (n,d)
MT=205 (n,xt) cross section
MT=206 (n,xHe3) cross section
Calculated by the POD code /8/.
MT=207 (n,xa) cross section
Sum of (n,na) and (n,a)
MF= 4 Angular distributions of emitted neutrons
MT= 2 Elastic scattering
The OPTMAN /10/ & POD calculations /8/.
MF= 6 Energy-angle distributions of emitted particles
MT= 16 (n,2n) reaction
MT= 17 (n,3n) reaction
MT= 22 (n,na) reaction
MT= 28 (n,np) reaction
MT= 32 (n,nd) reaction
Neutron spectra calculated by the POD code /8/.
MT= 51-90 (n,n') reaction
Neutron angular distributions calculated by
OPTMAN /10/ & POD /8/.
MT= 91 (n,n') reaction
Neutron spectra calculated by the POD code /8/.
MT= 203 (n,xp) reaction
MT= 204 (n,xd) reaction
MT= 205 (n,xt) reaction
MT= 206 (n,xHe3) reaction
MT= 207 (n,xa) reaction
Light-ion spectra calculated by the POD code /6/.
MF=12 Gamma-ray multiplicities
MT= 3 Non-elastic gamma emission
Calculated by the POD code /8/.
MF=14 Gamma-ray angular distributions
MT= 3 Non-elastic gamma emission
Assumed to be isotropic.
MF=15 Gamma-ray spectra
MT= 3 Non-elastic gamma emission
Calculated by the POD code /8/.
***************************************************************
* Nuclear Model Calculations with POD Code /8/ *
***************************************************************
1. Theoretical models
The POD code is based on the spherical optical model, the
distorted-wave Born approximaiton (DWBA), one-component exciton
preequilibrium model, and the Hauser-Feshbach-Moldauer statis-
tical model. With the preequilibrium model, semi-empirical
pickup and knockout process can be taken into account for
composite-particle emission. The gamma-ray emission from the
compound nucleus can be calculated within the framework of the
exciton model. The code is capable of reading in particle
transmission coefficients calculated by separate spherical or
coupled-channel optical model code. In this evaluation, the OPTMAN
code /10/ was employed for neutrons, while the ECIS code
/11/ was adopted for charged particles.
2. Optical model & parameters
Neutrons:
Model: Coupled-channel model based on the rigid-rotor model
OMP : Based on the Coupled-channel optical potential /12/
The original Parameters were slightly modified as
listed below to reproduce experimental total cross
sections measured by Camarda et al /13/.
------------------------------------------------------------
- Real-volume term
VR0= -3.85E+1 MeV VR1= 2.70E-2 MeV VR2= 1.20E-4 MeV
VR3= 3.50E-7 MeV VRLA= 9.49E+1 MeV ALAVR= 4.22E-3
r= 1.21E+0 a= 6.30E-1
- Imaginary-surface term
WDBW= 1.30E+1 MeV WDWID= 1.40E+1 MeV ALAWD= 1.40E-2
r= 1.21E+0 a= 6.75E-1
- Imaginary-volume term
WCBW= 1.70E+1 MeV WCWID= 1.05E+2 MeV
r= 1.21E+0 a= 6.75E-1
- Spin-orbit term
VS= 6.35E+0 MeV ALASO= 5.00E-3
WSBW= -3.10E+0 MeV WSWID= 1.60E+2 MeV
r= 1.06E+0 a= 5.90E-1
- Isospin coefficients
CISO= 2.43E+1 WCISO= 1.80E+1 CCOUL= 9.00E-1
- Deformation parameter
Beta2= -1.28E-1
------------------------------------------------------------
Protons:
Model: Spherical
OMP : Koning and Delaroche /14/
Deuterons:
Model: Spherical
OMP : Bojowald et al. /15/
Tritons:
Mode: Spherical
OMP : Becchetti and Greenlees /16/
He-3:
Model: Spherical
OMP : Becchetti and Greenlees /16/
Alphas:
Model: Spherical
OMP : A simplified folding model potential /17/
(The nucleon OMP was taken form Ref./12/.)
3. Level scheme of Ce-142
------------------------------------
No. Ex(MeV) J PI CC
------------------------------------
0 0.00000 0 + *
1 0.64129 2 + *
2 1.21938 4 +
3 1.53610 2 +
4 1.65260 3 -
5 1.74200 4 +
6 2.00430 2 +
7 2.01420 1 -
8 2.03060 0 +
9 2.04350 2 -
10 2.11400 0 +
11 2.12500 3 -
12 2.18160 2 +
13 2.18720 1 -
14 2.27900 0 +
15 2.36450 1 -
------------------------------------
Levels above 2.37450 MeV are assumed to be continuous.
4. Level density parameters
Energy-dependent parameters of Mengoni-Nakajima /18/ were used
----------------------------------------------------------
Nuclei a* Pair Esh T E0 Ematch Elv_max
1/MeV MeV MeV MeV MeV MeV MeV
----------------------------------------------------------
Ce-143 18.015 1.003 0.415 0.562 -0.412 5.329 1.173
Ce-142 17.282 2.014 -0.311 0.610 0.530 6.671 2.365
Ce-141 17.686 1.011 -1.072 0.493 0.659 3.613 1.942
Ce-140 17.074 2.028 -1.942 0.640 0.903 6.384 2.481
La-142 17.180 0.000 -0.112 0.617 -1.592 4.824 0.361
La-141 16.464 1.011 -0.489 0.665 -0.737 6.277 0.929
La-140 17.665 0.000 -1.411 0.615 -1.257 4.391 0.602
Ba-140 17.074 2.028 -1.371 0.607 1.003 6.085 2.704
Ba-139 20.276 1.018 -2.224 0.511 0.373 4.093 2.038
Ba-138 16.830 2.043 -3.130 0.710 0.829 6.866 3.155
----------------------------------------------------------
5. Gamma-ray strength functions
M1, E2: Standard Lorentzian (SLO)
E1 : Generalized Lorentzian (GLO) /19/
6. Preequilibrium process
Preequilibrium is on for n, p, d, t, He-3, and alpha.
Preequilibrium capture is on.
References
1) M.Ohkubo et al.: Proc. Int. Conf. on Nuclear Data for
Basic and Applied Science, Santa-Fe, Vol.2, p.1623 (1985).
2) S.F.Mughabghab et al.: "Neutron Cross Sections, Vol. I,
Part A," Academic Press (1981).
3) V.Benzi, G.Reffo: CCDN-NW/10 (1969).
4) L.M.Bollinger, G.E.Thomas: Phys. Rev., 171, 1293 (1968).
5) S.F.Mughabghab, "Atlas of Neutron Resonances",
Elsevier (2006).
6) L.P.Roy, L.Yaffe: Can. J. Chem., 34, 1023 (1956).
7) J.Alstad et al.: J. Inorg. Nucl. Chem., 29, 2155 (1967).
8) A.Ichihara et al., JAEA-Data/Code 2007-012 (2007).
9) Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999)
[in Japanese].
10) E.Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).
11) J.Raynal, CEA Saclay report, CEA-N-2772 (1994).
12) S.Kunieda et al., J. Nucl. Sci. Technol. 44, 838 (2007).
13) Camarda et al., Phys. Rev. C 29, 2106 (1984).
14) A.J.Koning, J.P.Delaroche, Nucl. Phys. A713, 231 (2003).
15) Bojowald et al., Phys. Rev. C 38, 1153 (1988).
16) F.D.Becchetti,Jr., G.W.Greenlees, "Polarization
Phenomena in Nuclear Reactions," p.682, The University
of Wisconsin Press (1971).
17) D.G.Madland, NEANDC-245 (1988), p. 103.
18) A.Mengoni, Y.Nakajima, J. Nucl. Sci. Technol. 31, 151
(1994).
19) M.Brink, Ph.D thesis, Oxford University, 1955.