98-Cf-252

 98-CF-252 JAERI      EVAL-MAR87 T.NAKAGAWA                       
 JAERI-M 88-004       DIST-SEP89                                  
----JENDL-3.2         MATERIAL 9861                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
87-03 NEW EVALUATION WAS MADE BY T.NAKAGAWA (JAERI).              
      DETAILS ARE DESCRIBED IN REF. /1/.                          
                                                                  
MF=1  GENERAL INFORMATION                                         
  MT=451   COMMENTS AND DICTIONARY                                
  MT=452   NUMBER OF NEUTRONS PER FISSION                         
             SUM OF MT=455 AND MT=456                             
  MT=455   DELAYED NEUTRON DATA                                   
             BASED ON SEMI-EMPIRICAL FORMULA BY TUTTLE /2/.       
  MT=456   NUMBER OF PROMPT NEUTRONS PER FISSION                  
             BASED ON SEMI-EMPIRICAL FORMULA BY HOWERTON /3/.     
                                                                  
MF=2,MT=151  RESONANCE PARAMETERS                                 
  RESOLVED RESONANCE PARAMETERS (MLBW) : 1.0E-5 EV TO 1 KEV       
    RESONANCE PARAMETERS WERE TAKEN FROM MOORE EL AL. /4/ BY      
    ASSUMING AN AVERAGE VALUE OF RADIATIVE CAPTURE WIDTH (0.035   
    EV) AND FISSION WIDTH (0.035 EV).  TWO HYPOTHETICAL RESONANCES
    AT 1.4 AND -3.5 EV WERE ADOPTED TO REPRODUCE THE 2200-M/S     
    CROSS SECTIONS AND RESONANCE INTEGRALS /5,6/.  SCATTERING     
    RADIUS OF 9.23 FM WAS ESTIMATED FROM THE SHAPE ELASTIC        
    SCATTERING CROSS SECTION CALCULATED WITH CASTHY /7/ FROM      
    OPTICAL POTENTIAL PARAMETERS GIVEN BELOW.                     
  UNRESOLVED RESONANCES                : 1 TO 30 KEV              
    PARAMETERS WERE ESTIMATED FROM RESOLVED RESONANCES AND        
    ADJUSTED SO AS TO REPRODUCE THE EVALUATED FISSION AND CAPTURE 
    CROSS SECTIONS BY USING ASREP /8/.  VALUES OF THE PARAMETERS  
    ARE D-OBS = 27 EV, R = 8.9 FM AND S0, S1, CAPTURE AND FISSION 
    WIDTHS ARE AS FOLLOWS.                                        
           ENERGY      S0        S1     CAPT-WIDTH  FISS-WIDTH    
            1.0 KEV   1.22-4    3.37-4    0.035 EV   0.056 EV     
           30.0       1.22-4    3.37-4    0.035      0.096        
                                                                  
  CALCULATED 2200 M/S CROSS SECTIONS AND RESONANCE INTEGRALS      
                   2200 M/S VALUE           RES. INT.             
      TOTAL          64.77   B                 -                  
      ELASTIC        11.04   B                 -                  
      FISSION        33.03   B               111.  B              
      CAPTURE        20.71   B                47.4 B              
                                                                  
MF=3  NEUTRON CROSS SECTIONS                                      
    BELOW 30 KEV, CROSS SECTIONS ARE REPRESENTED WITH RESONANCE   
    PARAMETERS.  ABOVE 30 KEV, DATA WERE MAINLY CALCULATED WITH   
    OPTICAL AND STATISTICAL MODELS.                               
                                                                  
 1) THE OPTICAL MODEL CALCULATION WAS PERFORMED WITH CODE CASTHY  
    /7/.  OPTICAL POTENTIAL PARAMETERS USED WERE OBTAINED /9/ BY  
    FITTING THE TOTAL CROSS SECTION MEASURED BY PHILLIPS AND HOWE 
    /10/ FOR AM-241:                                              
           V = 43.4 - 0.107*EN                      (MEV)         
           WS= 6.95 - 0.339*EN + 0.0531*EN**2       (MEV)         
                   (IN THE DERIVATIVE WOODS-SAXON FORM)           
           WV= 0             , VSO = 7.0            (MEV)         
           R = RSO = 1.282   , RS = 1.29            (FM)          
           A = ASO = 0.60    , B  = 0.5             (FM)          
 2) IN THE STATISTICAL CALCULATION, THE FISSION, (N,2N), (N,3N)   
    AND (N,4N) CROSS SECTIONS WERE CONSIDERED AS THE COMPETING    
    PROCESS CROSS SECTIONS.                                       
 3) THE LEVEL DENSITY PARAMETERS WERE DERIVED FROM RESONANCE      
    LEVEL SPACINGS AND LOW LAYING EXCITED LEVELS ON THE BASIS OF  
    GILBERT-CAMERON'S FORMULA /11/.                               
      ----------------------------------------------------------- 
              ISOTOPE     249      250      251      252      253 
      ----------------------------------------------------------- 
             A(1/MEV)    29.4     31.2     32.2     31.6     32.2 
     SPIN-CUTOFF FACT   31.25    32.36    32.97    32.74    33.14 
       PAIRING E(MEV)    1.16    1.673     0.77    1.635     0.77 
           TEMP.(MEV)   0.3693  0.4025   0.3809   0.3927   0.3322 
             C(1/MEV)   1.625    2.093    14.84    1.895     3.59 
              EX(MEV)   3.954    5.418    4.204    5.233    3.226 
      ----------------------------------------------------------- 
                                                                  
  MT=1,2  TOTAL AND ELASTIC SCATTERING                            
    THE OPTICAL MODEL CALCULATION WAS ADOPTED.                    
                                                                  
  MT=4, 51 TO 59 AND 91 INELASTIC SCATTERING                      
    THE LEVEL SCHEME WAS TAKEN FROM REF. /12/.                    
                                                                  
          NO.     ENERGY(KEV)       SPIN-PARITY                   
       --------------------------------------------               
         GROUND         0.0            0 +                        
           1           45.75           2 +                        
           2          151.73           4 +                        
           3          804.82           2 +                        
           4          830.81           2 -                        
           5          845.72           3 +                        
           6          867.51           3 -                        
           7          900.3            4 +                        
           8          917.03           4 -                        
           9          969.83           3 +                        
       --------------------------------------------               
        LEVELS ABOVE 1.03 MEV WERE ASSUMED TO BE OVERLAPPING.     
                                                                  
  MT=16, 17 AND 37  (N,2N), (N,3N) AND (N,4N)                     
    CALCULATED WITH EVAPORATION MODEL BY TAKING THE COMPOUND      
    NUCLEUS FORMATION CROSS SECTION CALCULATED WITH OPTICAL MODEL.
                                                                  
  MT=18   FISSION                                                 
    EVALUATED ON THE BASIS OF EXPERIMENTAL DATA BY MOORE EL AL.   
    /4/.                                                          
                                                                  
  MT=102 RADIATIVE CAPTURE                                        
    CALCULATED WITH CASTHY.  THE AVERAGE RADIATIVE WIDTH OF 0.035 
    EV AND S-WAVE LEVEL SPACING OF 27 EV WERE ASSUMED.            
                                                                  
  MT=251 MU-BAR                                                   
    CALCULATED WITH CASTHY.                                       
                                                                  
MF=4  ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS                 
  MT=2,51-59        CALCULATED WITH OPTICAL MODEL.                
  MT=16,17,18,37,91 ISOTROPIC DISTRIBUTIONS IN THE LABORATORY     
      SYSTEM WERE ASSUMED.                                        
                                                                  
MF=5  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS                  
  MT=16,17,37,91   EVAPORATION SPECTRUM ASSUMED.                  
  MT=18            MAXWELLOAN FISSION SPECTRUM.                   
                      TEMPERATURE ESTIMATED FROM SYSTEMATICS OF   
                      SMITH ET AL./13/.                           
                                                                  
REFERENCES                                                        
 1) NAKAGAWA, T.: JAERI-M 88-004 (1987).                          
 2) TUTTLE, R.J.: INDG(NDS)-107/G+SPECIAL, P.29 (1979).           
 3) HOWERTON, R.J.: NUCL. SCI. ENG., 62, 438 (1977).              
 4) MOORE, M.S., ET AL.: PHYS. REV., C4, 273 (1971).              
 5) HALPERIN, J., ET AL.: NUCL. SCI. ENG., 37, 228 (1969).        
 6) HALPERIN, J., ET AL.: ORNL 4706, 53 (1971).                   
 7) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975).           
 8) KIKUCHI, Y.: PRIVATE COMMUNICATION.                           
 9) IGARASI, S. AND NAKAGAWA T.: JAERI-M 8342 (1979).             
10) PHILLIPS, T.W. AND HOWE, F.R.: NUCL. SCI. ENG., 69, 375(1979).
11) GILBERT A. AND CAMERON A.G.W. : CAN. J. PHYS., 43, 1446(1965).
12) SCHMORAK, M.R.: NUCL. DATA SHEETS, 32, 87 (1981).             
13) SMITH A.B. ET AL.: ANL/NDM-50 (1979).