14-Si- 28

 14-Si- 28 JAEA       EVAL-AUG07 K.Shibata, S.Kunieda             
                      DIST-MAY10                       20100127   
----JENDL-4.0         MATERIAL 1425                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
History                                                           
07-08 Evaluated by K.Shibata and S.Kunieda.                       
10-01 Compiled by K.Shibata.                                      
                                                                  
MF= 1 General information                                         
  MT=451 Descriptive data and directory                           
                                                                  
MF= 2  Resonance parameters                                       
  MT=151 Resolved resonance parameters                            
    Resolved resonance region (Reich-Moore formula) : Below 1.75  
    MeV                                                           
      The resolved resonance parameters were taken from the       
      ENDF/B-VII.0 data, which were evaluated by Leal et al./1/   
                                                                  
      The following comments were also taken from ENDF/B-VII.0:   
      ------------------------------------------------------------
      The following data were included in the analysis:           
      (1) Total cross section data of Perey et al. /2/ for        
        natural silicon, measured on the 47-m flight path at the  
        Oak Ridge Electron Linear Accelerator (ORELA)             
      (2) Transmission data of Harvey et al. /3/ for natural      
        silicon measured on the 200-m flight path at ORELA        
      (3) Total cross section data of Larson et al. /4/,          
        measured on the 80- and 200-m flight paths at ORELA       
      (4) 29Si-oxide /5/ and 30Si-oxide /6/ transmission          
        data of Harvey et al., measured on the 80-m ORELA flight  
        path                                                      
      (5) Elastic scattering thermal cross section for 28Si       
        1.992+-0.006 barns from Mughabghab /7/.  Capture          
        thermal cross section 0.169+-0.004 barns from Raman et    
        al. /8/.  Values given by resonance parameters are        
        1.992 and 0.169 barns respectively.                       
      ------------------------------------------------------------
                                                                  
    Thermal cross sections and resonance integrals at 300 K       
    ----------------------------------------------------------    
                     0.0253 eV           res. integ. (*)          
                      (barns)              (barns)                
    ----------------------------------------------------------    
     Total           2.1612E+00                                   
     Elastic         1.9920E+00                                   
     n,gamma         1.6915E-01           8.4180E-02              
    ----------------------------------------------------------    
       (*) Integrated from 0.5 eV to 10 MeV.                      
                                                                  
MF= 3 Neutron cross sections                                      
                                                                  
  MT=  1 Total cross section                                      
    Below 12.5 MeV, the cross sections were taken from the        
    JENDL-3.3 evaluation that was based on experimental data.     
    Above 12.5 MeV, the cross sections were calculated using      
    TNG /9/.                                                      
                                                                  
  MT=  2 Elastic scattering cross section                         
    Obtained by subtracting non-elastic cross sections from total 
    cross sections.                                               
                                                                  
  MT=  4,51-91 (n,n') cross section                               
    Calculated with TNG code /9/. For MT=51, the cross sections   
    were replaced by the data measured by Sullivan et al./10/     
    below 4.15 MeV.                                               
    As for MT=91, the cross sections, which were calcuated with   
    TNG, were modified between 12 and 14.5 MeV.                   
                                                                  
  MT= 16 (n,2n) cross section                                     
    Calculated with TNG code /9/.                                 
                                                                  
  MT= 22 (n,na) cross section                                     
    Calculated with TNG code /9/.                                 
                                                                  
  MT= 28 (n,np) cross section                                     
    Taken from JENDL-3.3.                                         
                                                                  
  MT=102 Capture cross section                                    
    Calculated with TNG code /9/.                                 
                                                                  
  MT=103 (n,p) cross section                                      
    Calculated from MT=600-649.                                   
                                                                  
  MT=107 (n,a) cross section                                      
    Calculated from MT=800-849.                                   
                                                                  
  MT=600-649 partial (n,p) cross section                          
    Calculated with TNG code /9/.  For MT=600,601, the cross      
    sections were replaced with the data measured by Bateman et   
    al./11/ between 5.513 and 8.973 MeV with a scaling factor of  
    0.5.                                                          
                                                                  
  MT=800-849 partial (n,a) cross section                          
    Calculated with TNG code /9/.  For MT=800, the cross sections 
    were replaced with the data measured by Bateman et al./11/    
    between 5.853 and 7.986 MeV.  Finally, the cross section of   
    MT=849 was increased to reproduce the total (n,a) cross       
    section of JENDL-3.3 above 11 MeV.                            
                                                                  
MF= 4 Angular distributions of emitted neutrons                   
  MT=  2 Elastic scattering                                       
    Calculated with TNG code /9/.  The shape elastic scattering   
    component was calculated using OPTMAN code./12/               
                                                                  
MF= 6 Energy-angle distributions of emitted particles             
  MT= 16 (n,2n) reaction                                          
    Neutron and gamma-ray spectra calculated with TNG/9/.         
                                                                  
  MT= 22 (n,na) reaction                                          
    Neutron, alpha-particle, and gamma-ray spectra calculated with
    TNG/9/.                                                       
                                                                  
  MT= 28 (n,np) reaction                                          
    Neutron, proton, and gamma-ray spectra calculated with TNG/9/.
                                                                  
  MT= 51-66 (n,n') reaction                                       
    Neutron angular distributions and discrete gamma-ray spectra  
    calculated with TNG/9/.                                       
                                                                  
  MT= 91 (n,n') reaction                                          
    Neutron spectra, and discrete-continuous gamma-ray spectra    
    calculated with  with TNG/9/.                                 
                                                                  
  MT=102 (n,gamma) reaction                                       
    Gamma-ray spectra calcualted with TNG/9/.                     
                                                                  
  MT=600-614 (n,p) reactions leading to discrete levels           
    Proton angular distributions and discrete gamma-ray spectra   
    calculated with TNG/9/.                                       
                                                                  
  MT=649 (n,p) reaction leading to continuum levels               
    Proton spectra and discrete-continuous gamma-ray spectra      
    calculated with TNG/9/.                                       
                                                                  
  MT=800-831 (n,a) reactions leading to discrete levels           
    Alpha-particle angular distributions and gamma-ray spectra    
    calculated with TNG/9/.                                       
                                                                  
  MT=849 (n,a) reaction leading to continuum levels               
    Alpha-particle spectra and discrete-continuous gamma-ray      
    spectra calculated with TNG/9/.                               
                                                                  
                                                                  
                                                        
                                                                  
***************************************************************   
*        Nuclear Model Calculations with TNG Code /9/         *   
***************************************************************   
The description of the model calcualtions is given in Ref.13.     
                                                                  
< Optical model parameters >                                      
Neutrons and protons:                                             
  Coupled-channel optical model parameters /13/                   
Alphas:                                                           
  The potential parameters were obtained using the code developed 
  by Kumar and Kailas./14/                                        
                                                                  
< Level scheme of Si- 28 >                                        
  -------------------------                                       
   No.   Ex(MeV)     J  PI                                        
  -------------------------                                       
    0    0.00000     0   +                                        
    1    1.77900     2   +                                        
    2    4.61790     4   +                                        
    3    4.97990     0   +                                        
    4    6.27620     3   +                                        
    5    6.69140     0   +                                        
    6    6.87880     3   -                                        
    7    6.88770     4   +                                        
    8    7.38060     2   +                                        
    9    7.41630     2   +                                        
   10    7.79900     3   +                                        
   11    7.93350     2   +                                        
   12    8.25870     2   +                                        
   13    8.32840     1   +                                        
   14    8.41330     4   -                                        
   15    8.54360     6   +                                        
   16    8.58870     3   +                                        
                                                                  
The direct-reaction process was taken into accout for the 1st, 2nd
and 15th levels by the coupled-channel method.                    
                                                                  
< Level density parameters >                                      
Energy dependent parameters of Mengoni-Nakajima /15/ were used.   
  ----------------------------------------------------------      
  Nuclei    a*    Pair    Esh     T     E0    Ematch Econt        
          1/MeV   MeV     MeV    MeV    MeV    MeV    MeV         
  ----------------------------------------------------------      
  Si- 29   5.138  2.228 -3.404  1.964  0.625 10.099  7.521        
  Si- 28   4.489  4.536 -4.401  2.454  1.949 15.409  8.819        
  Si- 27   4.864  2.309 -2.076  1.916  0.076 10.784  5.262        
  Al- 28   4.508  0.000 -2.180  2.170 -3.293 10.786  3.012        
  Al- 27   4.142  2.309 -2.456  2.493 -2.390 16.024  6.948        
  Mg- 25   4.587  2.400 -0.869  1.901 -0.347 11.340  6.169        
  Mg- 24   3.964  4.899 -1.374  2.139  2.819 13.649 10.161        
  ----------------------------------------------------------      
                                                                  
References                                                        
 1) L.C. Leal et al., Proc. Int. Conf. Nuclear Data for Science   
    and Technology, Trieste, 1997, Part I, 929 (1997).            
 2) F.G. Perey, T.A. Love, W.E. Kinney, Oak Ridge National        
    Laboratory report ORNL-4823 [ENDF-178] (1972).                
 3) J.A. Harvey, private communication (1996).                    
 4) D.C. Larson, C.H. Johnson, J.A. Harvey, and N.W. Hill,        
    "Measurement of the neutron total cross section of silicon    
    from 5 eV to 730 keV," Oak Ridge National Laboratory report   
    ORNL/TM-5618 (1976)                                           
 5) J.A. Harvey, private communication (1996).                    
 6) J.A. Harvey, W.M. Good, R.F. Carlton, et al., Phys.Rev.C      
    28, 24 (1983).                                                
 7) S.F. Mughabghab, M. Divadeenam, N.E. Holden,  Neutron         
    Cross Sections, Vol. 1, Part A: Z=1-60, (Academic Press, NY,  
    1981).                                                        
 8) S. Raman, et al., Phys.Rev.C 46, 972 (1992).                  
 9) C.Y. Fu, ORNL/TM-7042 (1980); K. Shibata, C.Y. Fu, ORNL/TM-   
    10093 (1986).                                                 
10) N.B. Sullivan et al., Nucl. Sci. Eng., 70, 294 (1979).        
11) F.B. Bateman et al., Phys. Rev., 55, 133 (1997).              
12) E.Sh. Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).   
13) K. Shibata, S. Kunieda, J. Nucl. Sci. Technol., 45, 123       
    (2008).                                                       
14) A. Kumar, S. Kailas, a computer code contained in RIPL-2,     
    Bhabha Atomic Research Center, private communication (2002).  
15) A. Mengoni, Y. Nakajima, J. Nucl. Sci. Technol., 31, 151      
    (1994).