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.