89-Ac-227

 89-AC-227 TIT        EVAL-AUG88 N.TAKAGI                         
                      DIST-SEP89                                  
----JENDL-3.2         MATERIAL 8931                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
88-08 NEW EVALUATION WAS MADE BY N. TAKAGI (TOKYO INSTITUTE OF    
      TECHNOLOGY, TIT)                                            
                                                                  
MF=1  GENERAL INFORMATION                                         
  MT=451   COMMENT AND DICTIONARY                                 
  MT=452   NUMBER OF NEUTRONS PER FISSION                         
            EVALUATED WITH SEMI EMPIRICAL FORMULA OF HOWERTON/1/. 
                                                                  
MF=2  RESONANCE PARAMETERS                                        
  MT=151   RESONANCE PARAMETERS                                   
    NO RESONANCE PARAMETERS WERE GIVEN.                           
                                                                  
  2200-M/S CROSS SECTIONS AND RESONANCE INTEGRALS                 
                      2200 M/S VALUE       RES. INT.              
        TOTAL           902.40    B            -                  
        ELASTIC          12.40    B            -                  
        FISSION           0.00029 B          0.138 B              
        CAPTURE         890.00    B          1650  B              
                                                                  
MF=3  NEUTRON CROSS SECTIONS                                      
  MT=1  TOTAL CROSS SECTION                                       
        BELOW  36 EV, CALCULATED AS SUM OF MT'S = 2, 18 AND 102.  
        ABOVE  36 EV, OPTICAL MODEL CALCULATION WAS MADE WITH     
        CASTHY/2/.  THE POTENTIAL PARAMETERS/3/ USED ARE AS       
        FOLLOWS,                                                  
           V = 41.0 - 0.05*EN                      (MEV)          
           WS= 6.4 - 0.15*SQRT(EN)                 (MEV)          
           WV= 0             , VSO = 7.0           (MEV)          
           R = RSO = 1.31    , RS = 1.38            (FM)          
           A = ASO = 0.47    , B  = 0.47            (FM)          
                                                                  
  MT=2  ELASTIC SCATTERING CROSS SECTION                          
        BELOW 36 EV, THE CONSTANT CROSS SECTION OF 12.4 BARNS WAS 
        ASSUMED, WHICH WAS THE SHAPE ELASTIC SCATTERING CROSS     
        SECTION CALCULATED WITH OPTICAL MODEL.  ABOVE THIS ENERGY,
        OPTICAL MODEL CALCULATION WAS ADOPTED.                    
                                                                  
  MT=4,51-59,91  INELASTIC SCATTERING CROSS SECTIONS.             
        OPTICAL AND STATISTICAL MODEL CALCULATION WAS MADE WITH   
        CASTHY/2/.  THE LEVEL SCHEME WAS TAKEN FROM REF. 4.       
                   NO         ENERGY(KEV)   SPIN-PARITY           
                  G.S.             0.0         3/2 -              
                    1             27.36        3/2 +              
                    2             29.95        5/2 -              
                    3             46.37        5/2 +              
                    4             74.14        7/2 -              
                    5             84.56        7/2 +              
                    6            110.00        9/2 +              
                    7            126.85        9/2 -              
                    8            187.36       11/2 -              
                    9            210.92       13/2 +              
        LEVELS ABOVE 273 KEV WERE ASSUMED TO BE OVERLAPPING.      
        THE LEVEL DENSITY PARAMETERS WERE TAKEN FROM REF. 5.      
                                                                  
  MT=16,17,37  (N,2N), (N,3N) AND (N,4N) REACTION CROSS SECTIONS  
        CALCULATED WITH EVAPORATION MODEL.                        
                                                                  
  MT=18  FISSION CROSS SECTION                                    
        MEASURED THERMAL CROSS SECTION OF 0.29 MILLI-BARN WAS     
        TAKEN FROM REF. 6 , AND 1/V FORM WAS ASSUMED BELOW 36 EV. 
        ABOVE FISSION THRESHOLD ENERGY, EXPERIMENTAL DATA/7/ WERE 
        ADOPTED, AND IN THE ENERGY RANGE BETWEEN 36 EV AND FISSION
        THRESHOLD, CROSS SECTION WAS ASSUMED TO BE CONSTANT WITH  
        THE VALUE AT 36 EV.                                       
                                                                  
  MT=102  CAPTURE CROSS SECTION                                   
        MEASURED THERMAL CROSS SECTION OF 890 BARNS WAS TAKEN FROM
        REF. 6 , AND 1/V FORM WAS ASSUMED BELOW 36 EV.  THE CROSS 
        SECTION NEAR 36 EV WAS ADJUSTED SO AS TO REPRODUCE THE    
        MEASURED RESONANCE INTEGRAL/6/.  ABOVE 0.45 EV, CROSS     
        SECTION WAS CALCULATED WITH CASTHY.  THE GAMMA-RAY        
        STRENGTH FUNCTION WAS ESTIMATED FROM GAMMA-GAMMA = 0.040  
        EV AND LEVEL SPACING = 72 EV.                             
                                                                  
  MT=251  MU-L                                                    
        CALCULATED WITH CASTHY.                                   
                                                                  
MF=4  ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS                 
  MT=2,51-59,91       CALCULATED WITH OPTICAL MODEL.              
  MT=16,17,18,37      ISOTROPIC IN THE LAB SYSTEM.                
                                                                  
MF=5  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS                  
  MT=16,17,37,91      EVAPORATION SPECTRA                         
         OBTAINED FROM LEVEL DENSITY PARAMETERS.                  
                                                                  
  MT=18               MAXWELLIAN FISSION SPECTRUM.                
        TEMPERATURE WAS ESTIMATED FROM Z**2/A DEPENDENCE/8/.      
                                                                  
REFERENCES                                                        
 1) HOWERTON R.J.: NUCL. SCI. ENG., 62, 438 (1977).               
 2) IGARASI S.: J.NUCL.SCI.TECHNOL.,12,67 (1975).                 
 3) OHSAWA T., OHTA M.: J. NUCL. SCI. TECHNOL., 18, 408 (1981).   
 4) MAPLES C.: NUCL. DATA SHEETS, 22, 275 (1977).                 
 5) GILBERT A., CAMERON A.G.W.: CAN. J. PHYS., 43, 1446 (1965).   
 6) MUGHABGHAB S.F.: "NEUTRON CROSS SECTIONS, VOL.1, NEUTRON      
    RESONANCE PARAMETERS AND THERMAL CROSS SECTIONS , PART B,     
    Z=61-100", ACADEMIC PRESS (1984).                             
 7) KUKS I.M. ET AL.: YAD. FIZ. ISS., 26, 46 (1978).              
 8) SMITH A.B. ET AL.: ANL/NDM-50 (1979).