58-Ce-140 JAEA EVAL-FEB10 S.Kunieda, A.Ichihara, K.Shibata+
DIST-MAY10 20100223
----JENDL-4.0 MATERIAL 5837
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
10-02 Re-evaluation was performed for JENDL-4 above the resoloved
resonance region. The resonance parameters are the same as
those of JENDL-3.3 (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 200 keV
For JENDL-2, the resonance parameters were evaluated by
Kikuchi /1/. Neutron widths were obtained from data
measured by Hacken et al. /2/ and Camarda /3/, and
radiation widths from capture areas by Musgrove et al.
/4/ For the resonances only whose capture area was
measured, the neutron width was deduced by assuming the
average radiation width of 0.034+-0.029 eV for s-wave
resonances and 0.029+-0.008 eV for p-wave ones. A negative
resonance was added so as to reproduce the capture cross
section of 0.57+-0.04 barn and the elastic scattering cross
section of 2.83+-0.11 barns at 0.0253 eV /5/.
For JENDL-3.2, neutron widths of 14 resonances were
replaced with experimental data obtained by Ohkubo /6/
in the energy range from 2.5437 keV to 55.113 keV.
Parameters of the negative resonance were re-adjusted to the
above thermal cross sections /5/.
For JENDL-3.3, neutron widths of 2.5- to 55- keV levels
were modified on the basis of Ohkubo et al. /7/. Capture
widths of all levels were multiplied by a factor of 1.4 so
as to be consistent with a new capture cross section
measurement /8/. A negative level was modified and 1/v
corresction was aplied to the capture cross section.
No further update was made for JENDL-4.
- No unresolved resonance parameters are given.
Thermal cross sections & resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 3.46643E+00
Elastic 2.89398E+00
n,gamma 5.70396E-01 3.44622E-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 /9/ & POD calculations /10/.
MT= 3 Non-elastic cross section
Sum of partial non-elastic cross sections.
MT= 4,51-91 (n,n') cross section
The OPTMAN /9/ & POD calculations /10/.
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
Calculated by the POD code /10/.
MT=102 Capture cross section
Calculated by the POD code /10/. Gamma-ray strength
function was normalized to fit the experimental cross
sections measured by Harnood et al /8/.
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 /10/.
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 /10/.
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 /9/ & POD calculations /10/.
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 /10/.
MT= 51-90 (n,n') reaction
Neutron angular distributions calculated by
OPTMAN /9/ & POD /10/.
MT= 91 (n,n') reaction
Neutron spectra calculated by the POD code /10/.
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 /10/.
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 /10/.
***************************************************************
* Nuclear Model Calculations with POD Code /10/ *
***************************************************************
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 /9/ 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= 6.34E+0 MeV ALASO= 5.00E-3
WSBW= -3.10E+0 MeV WSWID= 1.60E+2 MeV
r= 1.05E+0 a= 5.90E-1
- Isospin coefficients
CISO= 2.43E+1 WCISO= 1.80E+1 CCOUL= 9.00E-1
- Deformation parameter
Beta2= 1.60E-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-140
------------------------------------
No. Ex(MeV) J PI CC
------------------------------------
0 0.00000 0 + *
1 1.59623 2 + *
2 1.90331 0 +
3 2.08325 4 +
4 2.10785 6 +
5 2.34788 2 +
6 2.34981 5 +
7 2.41201 3 +
8 2.46408 3 -
9 2.48092 4 +
------------------------------------
Levels above 2.49092 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-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
Ce-138 16.866 2.043 -0.407 0.654 0.240 7.301 2.237
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
La-138 16.770 0.000 -1.494 0.612 -0.947 3.973 0.642
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
Ba-136 16.959 2.058 -1.396 0.750 -0.538 8.774 2.223
----------------------------------------------------------
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) Kikuchi Y. et al.: JAERI-M 86-030 (1986).
2) Hacken G., et al.: USNDC-11, 79 (1974).
3) Camarda H.S.: Phys. Rev., C18, 1254 (1978).
4) Musgrove A.R. de L., et al.: Aust. J. Phys., 32, 213 (1979).
5) Mughabghab S.F. et al.: "Neutron Cross Sections, Vol. I,
Part A", Academic Press (1981).
6) Ohkubo M. et al.: Proc. Int. Conf. on Nuclear Data for Basic
and Applied Science, Santa-Fe., Vol.2, p.1623 (1985).
7) Ohkubu M., et al.: JAERI-M 93-012 (1993).
8) Harnood S., et al.: J. Nucl. Sci. Technol., 37, 740 (2000).
9) E.Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).
10) A.Ichihara et al., JAEA-Data/Code 2007-012 (2007).
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.