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.