58-Ce-141 JAEA EVAL-FEB10 S.Kunieda, A.Ichihara, K.Shibata+
DIST-MAY10 20100223
----JENDL-4.0 MATERIAL 5840
-----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 40 eV
For JENDL3.3, experimental data measured by Anufriev et
al./1/ for 6 resonances below 335 eV were used.
Resonance energies, neutron and radiation widths obtained
by Anufriev et al. were adopted. Total spin J was
determined with a random number method. Finally, a negative
resonance was added so as to reproduce the thermal capture
cross section given by Mughabghab et al./2/
For JENDL-4.0, the neutron width of 7.4-eV resonance was
modified. That of JENDL-3.3 was 10 times larger than
reported value. Total spin J of each resonance was
re-evaluated. Neutron width of -5.0-eV resonance was
adjusted to reproduce the capture cross section of 29+-3 b
/3/. Upper boundary of the resolved resonance region was
set to 40 eV instead of 350 eV of JENDL-3.3, because level-
missing was seen above this energy.
- 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 /4/.
The ASREP code /5/ 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 3.23139E+01
Elastic 3.28994E+00
n,gamma 2.90240E+01 1.48336E+02
----------------------------------------------------------
(*) 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 /6/ & POD calculations /4/.
MT= 3 Non-elastic cross section
Sum of partial non-elastic cross sections.
MT= 4,51-91 (n,n') cross section
The OPTMAN /6/ & POD calculations /4/.
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 /4/.
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 /4/.
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 /6/ & POD calculations /4/.
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 /4/.
MT= 51-90 (n,n') reaction
Neutron angular distributions calculated by
OPTMAN /6/ & POD /4/.
MT= 91 (n,n') reaction
Neutron spectra calculated by the POD code /4/.
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 /4/.
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 /4/.
***************************************************************
* Nuclear Model Calculations with POD Code /4/ *
***************************************************************
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 /6/ was employed for neutrons, while the ECIS code
/7/ 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 /8/
The original Parameters were slightly modified as
listed below to reproduce experimental total cross
sections measured by Camarda et al /9/.
------------------------------------------------------------
- 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= 6.34E+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= -1.00E-1
------------------------------------------------------------
Protons:
Model: Spherical
OMP : Koning and Delaroche /10/
Deuterons:
Model: Spherical
OMP : Bojowald et al. /11/
Tritons:
Mode: Spherical
OMP : Becchetti and Greenlees /12/
He-3:
Model: Spherical
OMP : Becchetti and Greenlees /12/
Alphas:
Model: Spherical
OMP : A simplified folding model potential /13/
(The nucleon OMP was taken form Ref./8/.)
3. Level scheme of Ce-141
------------------------------------
No. Ex(MeV) J PI CC
------------------------------------
0 0.00000 7/2 - *
1 0.66206 3/2 -
2 1.13700 1/2 -
3 1.35452 9/2 - *
4 1.36870 13/2 +
5 1.37800 9/2 -
6 1.49700 5/2 -
7 1.62650 3/2 +
8 1.69330 11/2 -
9 1.73900 7/2 -
10 1.78500 1/2 +
11 1.80870 3/2 -
12 1.81200 5/2 -
13 1.91500 9/2 -
14 1.94200 1/2 +
------------------------------------
Levels above 1.95200 MeV are assumed to be continuous.
4. Level density parameters
Energy-dependent parameters of Mengoni-Nakajima /14/ were used
----------------------------------------------------------
Nuclei a* Pair Esh T E0 Ematch Elv_max
1/MeV MeV MeV MeV MeV MeV MeV
----------------------------------------------------------
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
Ce-139 17.607 1.018 -1.120 0.492 0.694 3.570 1.985
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
La-139 16.263 1.018 -2.218 0.812 -1.629 8.151 1.257
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
Ba-137 18.884 1.025 -2.239 0.463 0.926 3.110 1.908
----------------------------------------------------------
5. Gamma-ray strength functions
M1, E2: Standard Lorentzian (SLO)
E1 : Generalized Lorentzian (GLO) /15/
6. Preequilibrium process
Preequilibrium is on for n, p, d, t, He-3, and alpha.
Preequilibrium capture is on.
References
1) B.A.Anufriev et al. : 1980 Kiev, Vol.2, p.136 (1980).
2) S.F.Mughabghab et al.: "Neutron Cross Sections, Vol. I,
Part A," Academic Press (1981).
3) P.M.Lantz et al.: Nucl. Sci. Eng., 20, 302 (1964).
4) A.Ichihara et al., JAEA-Data/Code 2007-012 (2007).
5) Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999)
[in Japanese].
6) E.Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).
7) J.Raynal, CEA Saclay report, CEA-N-2772 (1994).
8) S.Kunieda et al., J. Nucl. Sci. Technol. 44, 838 (2007).
9) Camarda et al., Phys. Rev. C 29, 2106 (1984).
10) A.J.Koning, J.P.Delaroche, Nucl. Phys. A713, 231 (2003).
11) Bojowald et al., Phys. Rev. C 38, 1153 (1988).
12) F.D.Becchetti,Jr., G.W.Greenlees, "Polarization
Phenomena in Nuclear Reactions," p.682, The University
of Wisconsin Press (1971).
13) D.G.Madland, NEANDC-245 (1988), p. 103.
14) A.Mengoni, Y.Nakajima, J. Nucl. Sci. Technol. 31, 151
(1994).
15) M.Brink, Ph.D thesis, Oxford University, 1955.