12-Mg- 25

 12-MG- 25 DEC,NEDAC  EVAL-MAR87 M.HATCHYA(DEC),T.ASAMI(NEDAC)    
                      DIST-MAR02 REV2-MAY01            20010517   
----JENDL-3.3         MATERIAL 1228                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
HISTORY                                                           
 87-03  New evaluation was made for JENDL-3.                      
 87-03  Compiled by T.Asami.                                      
 01-04  Gamma-ray production data were added.                     
        Compiled by K.Shibata.                                    
*****  modification for JENDL-3.3  ****************************** 
(1,451)            Updated.                                       
(3,251)            Deleted.                                       
(4,2)              Transformation matrix deleted.                 
(5,16-91)          INT=22.                                        
(12,16-107)        Added.                                         
(14,16-107)        Added.                                         
(15,16-107)        Added.                                         
***************************************************************** 
                                                                  
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 220 keV.                   
   Parameters were taken from the recommended data of BNL/1/ and  
   modified for some levels so as to reproduce the experi-        
   mental total cross section of the element Mg.                  
   The data for a negative resonance were added so as to reproduce
   the recommended thermal cross sections for capture and scatter-
   ing/1/.                                                        
   The data for some levels were modified so that the calculated  
   total cross sections of the element Mg were fitted to the      
   experimental data of Hibdon/2/ and Singh/3/.                   
   The scattering radius was assumed to be 4.9 fermi.             
   Calculated 2200 m/sec cross sections and resonance integrals   
   are as follows:                                                
           2200 m/s cross section(b)     res. integral(b)         
   elastic     2.60                                               
   capture     0.190                       0.0989                 
   total       2.79                                               
                                                                  
mf=3  Neutron cross sections                                      
  Below 220 keV, zero background cross section was given and  all 
  the cross-section data are reproduced from the evaluated resolv-
  ed resonance parameters with MLBW formula.                      
  Above 220 keV, the total and partial cross sections were given  
  pointwise.                                                      
 mt=1 Total                                                       
  Optical and statistical model calculation was made with         
  the casthy code/2/. The optical potential parameters used are:  
    V = 49.68,                Vso = 7.12   (MeV)                  
   Ws = 7.76 - 0.5*En,         Wv = 0      (MeV)                  
    r = 1.17,  rs = 1.09,  rso = 1.17      (fm)                   
    a = 0.6,   aso = 0.6,   b = 0.69       (fm)                   
 mt=2 Elastic scattering                                          
  Obtained by subtracting the sum of the partial cross sections   
  from the total cross section.                                   
 mt=4, 51-67, 91 Inelastic scattering                             
  Calculated with casthy/4/, taking account of the contribution   
  from the competing processes. The direct component was          
  calculated with the dwuck/5/.                                   
  The level data used in the above two calculations were taken    
  from ref./6/ as follows:                                        
    mt   level energy(MeV)   spin-parity                          
             0.0                 5/2+                             
    51       0.5851              1/2+                             
    52       0.9748              3/2+                             
    53       1.6118              7/2+                             
    54       1.9647              5/2+                             
    55       2.5638              1/2+                             
    56       2.7377              7/2+                             
    57       2.8011              3/2+                             
    58       3.4052              9/2+                             
    59       3.4137              3/2-                             
    60       3.9078              5/2+                             
    61       3.9707              7/2-                             
    62       4.0596              9/2+                             
    63       4.2770              1/2-                             
    64       4.3594              3/2+                             
    65       4.7114              9/2+                             
    66       4.7220              1/2-                             
    67       5.0122              7/2+                             
  Levels above 8.0 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 gnash code/7/ using the above optical      
   model parameters                                               
   The (n,p) cross sections were normalized to the experimental   
   data at 14 MeV of Bormann/8/.                                  
 mt=102      Capture                                              
   Calculated with the casthy code/4/ and normalized to 4.7 mb    
   at 30 keV.                                                     
                                                                  
mf=4  Angular distributions of secondary neutrons                 
 mt=2                                                             
   Calculated with the casthy code/4/.                            
 mt=51-67                                                         
   Calculated with the casthy code/4/ and the dwuck code/5/.      
 mt=91                                                            
   Calculated with the casthy code/4/.                            
 mt=16, 22, 28                                                    
   Isotropic in the laboratory system.                            
                                                                  
mf=5  Energy distributions of secondary neutrons                  
 mt=16, 22, 28, 91                                                
   Calculated with the gnash code/7/.                             
                                                                  
mf=12 Photon multiplicities and transition probabilities          
 mt=16,22,28,91,103,107                                           
   Calculated with gnash.                                         
 mt=51-67                                                         
   Stored under option-2 (transition probability array).          
 mt=102                                                           
   Calculated with casthy.                                        
                                                                  
mf=14 Photon angular distributions                                
 mt=16,22,28,51-67,91,102,103,107                                 
   Isotropic.                                                     
                                                                  
mf=15 Continuous photon energy spectra                            
 mt=16,22,28,91,103,107                                           
   Calculated with gnash.                                         
 mt=102                                                           
   Calculated with casthy.                                        
                                                                  
References                                                        
1) Mughabghab S.F. and Garber D.I. :"Neutron cross sections", Vol.
   1, Part B (1984).                                              
2) Hibdon C.T. : taken from exfor (1969).                         
3) Singh U.N. et al. : Phys. Rev. C10, 2150 (1974).               
4) Igarasi S. : J. Nucl. Sci. Tech. 12, 67 (1975).                
5) Kunz P.D. : unpublished.                                       
6) ENSDF(Evaluated Nuclear Structure Data File)                   
7) Young P.G. and Arthur E.D. : LA-6947 (1977).                   
8) Bormann M. et al. : 1966 Paris Conf. Vol.1, 225 (1967).