11-Na- 23

 11-NA- 23 JAERI      EVAL-AUG00 K.SHIBATA (JAERI)                
                      DIST-MAR02 REV3-AUG00            20020214   
----JENDL-3.3         MATERIAL 1125                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
HISTORY                                                           
 2000-8 New evaluation was performed by K.Shibata (JAERI) for     
        JENDL-3.3.                                                
 2002-1 Covariances were taken from JENDL-3.2 covariance file.    
                                                                  
mf=1  General information                                         
 mt=451  Descriptive data and dictionary                          
                                                                  
mf=2  Resonance parameters                                        
 mt=151  Resolved resonance parameters                            
   Resolved parameters for MLBW formula were given in the energy  
   region from 1.0e-5 eV to 350 keV.  Parameters were mainly taken
   from the recommended data of BNL /2/, and the data for some    
   levels were modified so that the calculated total cross sec-   
   tions for Na-23 were fitted to the experimental data.  The     
   scattering radius was assumed to be 5.2 fermi.  Calculated 2200
   m/sec cross sections and resonance integrals are as follows:   
                                                                  
           2200 m/s cross section(b)     res. integral(b)         
   elastic       3.024                                            
   capture       0.531                         0.3122             
   total         3.555                                            
                                                                  
   This part was taken from JENDL-3.2 without any modification.   
                                                                  
mf=3  Neutron cross sections                                      
  Below 350 keV, background cross section was given for the total 
  and elastic scattering cross sections.  The cross-section data  
  are reproduced from the evaluated resolved resonance parameters 
  with MLBW formula.  Above 350 keV, the total and partial cross  
  sections were given pointwise.                                  
 mt=1 Total                                                       
  In the energies between 350 keV and 14 MeV, evaluated based on  
  the experimental data of Cierjacks/3/ by tracing their fine     
  structures. Above 14 MeV, based on the experimental data of     
  Langsford/4/, Stoler/5/ and Larson/1/.  Modefication was done by
  T.Fukahori(jaeri) to be based on the experimental data of only  
  Larson/1/ above 1 MeV.                                          
  The total cross section was taken from JENDL-3.2 without any    
  modification.                                                   
 mt=2 Elastic scattering                                          
  Obtained by subtracting the sum of the partial cross sections   
  from the total cross section.                                   
 mt=4, 51-78, 91 Inelastic scattering                             
  The cross sections were calculated by using the TNG code /6/.   
  The direct cross sections were taken into account for mt=51,52, 
  53,56.  The deformation parameters were estimated by a weak     
  coupling model.                                                 
  For mt=51, the TNG calculations were replaced with the following
  data:                                                           
      Threshold - 2.15 MeV: Maerten et al./7/ multiplied by 1.25  
                            The factor of 1.25 was derived from   
                            a benchmark test made by N. Yamano/8/.
      2.15 - 4.0 MeV      : JENDL-3.2 mt=51                       
                                                                  
  The neutron optical potential parameters used are:              
    V = 45.82 - 0.2497*Ecm  ,     Vso = 5.5      (MeV)            
    Ws = 7.4162 + 0.0049*Ecm (MeV)                                
    r = 1.2572,  rs = 1.1393,  rso = 1.2687        (fm)           
    a = 0.61646, as = 0.60349, aso = 0.6198        (fm)           
                                                                  
  The level data used in the above calculations were taken        
  from RIPL /9/ as follows:                                       
    mt   level energy(MeV)   spin-parity                          
             0.0               3/2+                               
    51       0.440             5/2+                               
    52       2.076             7/2+                               
    53       2.391             1/2+                               
    54       2.640             1/2-                               
    55       2.704             9/2+                               
    56       2.982             3/2+                               
    57       3.678             3/2-                               
    58       3.848             5/2-                               
    59       3.914             5/2+                               
    60       4.430             1/2+                               
    61       4.775             7/2+                               
    62       5.379             5/2+                               
    63       5.534            11/2+                               
    64       5.742             5/2+                               
    65       5.766             3/2+                               
    66       5.927             7/2+                               
    67       5.964             3/2-                               
    68       6.042             7/2-                               
    69       6.115             5/2+                               
    70       6.195             5/2-                               
    71       6.236             9/2+                               
    72       6.308             1/2+                               
    73       6.354             9/2-                               
    74       6.578             5/2+                               
    75       6.618             5/2+                               
    76       6.735             3/2+                               
    77       6.820             5/2-                               
    78       6.868             3/2+                               
  Levels above 6.9 MeV were assumed to be overlapping.            
                                                                  
 mt=16, 22, 28, 103, 107    (n,2n),(n,na),(n,np),(n,p),(n,a)      
    Calculated with the TNG code. For mt=103, the TNG calculations
    were replaced with the JENDL-3.2 data below 11 MeV.           
 mt=102    capture                                                
    In the energy region from 350 keV to 10 MeV, the cross        
    sections were calculated by TNG.  Above 10 MeV, a constant    
    cross section of was assumed.                                 
                                                                  
mf=4  Angular distributions of secondary neutrons                 
 mt=2                                                             
    Calculated with the optical model.                            
 mt=51-78                                                         
    Calculated with the TNG code and the DWUCK code/10/.          
                                                                  
mf=6 Energy-angle distributions of secondary particles            
 mt=16, 22, 28, 91, 103, 107                                      
    Calculated with the TNG code.                                 
                                                                  
mf=12  Photon production multiplicities                           
 mt=4, 16, 22, 28, 51-78,102, 103, 107                            
   Calculated with the TNG code.                                  
   For mt=102, the measured data /11/ were taken into account     
   between 50 keV and 400 keV.                                    
                                                                  
mf=14  Photon angular distributions                               
 mt=4, 16, 22, 28, 51-78, 102, 103, 107                           
   Assumed to be isotropic.                                       
                                                                  
mf=15  Continuous photon energy spectra                           
 mt=4, 16, 22, 28, 102, 103, 107                                  
   Calculated with the TNG code.                                  
   For mt=102, the measured data /11/ were taken into account     
   between 50 keV and 400 keV.                                    
                                                                  
mf=33  Covariances of cross sections (ref.12)                     
 mt=1                                                             
   Based on experimental data.  A chi-value was 1.887.            
 mt=2                                                             
   Constructed from mt=1, 16, 22, 28, 51-91, 102, 103, and 107.   
 mt=4                                                             
   Constructed from mt=51-91.                                     
 mt=16                                                            
   Based on experimental data.  A chi-value was 1.36.             
 mt=22                                                            
   The covariances were obtained by using kalman.  A chi-value    
   was 2.54.                                                      
 mt=28                                                            
   The covariances were obtained by using kalman.  A chi-value    
   was 2.54.                                                      
 mt=51-91                                                         
   The covariances were obtained by using kalman.  A chi-value    
   was 3.72.                                                      
 mt=102                                                           
   Based on experimental data.  A chi-value was 3.97.             
 mt=103                                                           
   Based on experimental data.  A chi-value was 2.3.              
 mt=107                                                           
   Based on experimental data.  A chi-value was 2.61.             
                                                                  
mf=34  Covariances of angular distributions (ref.12)              
 mt=2                                                             
   The covariances were obtained by using kalman.  A chi-value    
   was 1.01.                                                      
                                                                  
                                                                  
References                                                        
 1) Larson D.C. et al. : ORNL/TM-5614 (1976).                     
 2) Mughabghab S.F. et al.:"Neutron Cross Sections", Vol. 1,      
    Part A (1981).                                                
 3) Cierjacks S. et al. : KfK-1000 (1969).                        
 4) Langsford A. et al. : 1965 Antwerp Conf. 529 (1965).          
 5) Stoler P. et al. : 1971 Knoxville Conf. Vol.1, 311 (1971).    
 6) Shibata K. and Fu C.Y.: ORNL/TM-10093 (1986).                 
 7) Maerten H. et al.: Taken from EXFOR (1994).                   
 8) Yamano N.: Private communication (2001).                      
 9) IAEA: "Handbook for Calculations of Nuclear Reaction Data:    
    Reference Input Parameter Library", IAEA-TECDOC-1034 (1998).  
10) Kunz P.D.: Unpublished.                                       
11) Igashira M.: Private communication (2000).                    
12) Shibata K. et al.: JAERI-Research 97-074 (1997).