90-Th-228

 90-TH-228 KINKI U.   EVAL-JUN87 T.OHSAWA                         
                      DIST-SEP89 REV2-JUN94                       
----JENDL-3.2         MATERIAL 9028                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
81-04 EVALUATION FOR JENDL-2 WAS MADE BY T. OHSAWA* AND M. OHTA   
      (KYUSHU UNIVERSITY).  DETAILS OF THE EVALUATION ARE         
      DESCRIBED IN REF. /1/. (*PRESENT ADDRESS: KINKI UNIVERSITY) 
83-11 FISSION SPECTRUM WAS ADDED.  RESONANCE FORMULA WAS CHANGED  
      TO MLBW FORMULA.  THE TOTAL, (N,2N) AND (N,3N) CROSS SEC-   
      TIONS WERE MODIFIED.                                        
87-06 ALMOST OF JENDL-2 DATA WERE ADOPTED FOR JENDL-3.            
      (MF3,MT17), (MF3,MT91) AND (MF3,MT102) WERE SLIGHTLY        
      MODIFIED IN HIGH ENERGY REGION.                             
         COMPILATION WAS MADE BY T.NAKAGAWA (JAERI).              
94-06 JENDL-3.2.                                                  
       NU-P, NU-D AND NU-TOTAL WERE MODIFIED.                     
      COMPILED BY T.NAKAGAWA (NDC/JAERI)                          
                                                                  
     *****   MODIFIED PARTS FOR JENDL-3.2   ********************  
      (1,452), (1,455), (1,456)                                   
     ***********************************************************  
                                                                  
                                                                  
MF=1 GENERAL INFORMATION                                          
  MT=451 COMMENT AND DICTIONARY                                   
  MT=452 NUMBER OF NEUTRONS PER FISSION                           
      SUM OF NU-P NAD NU-D.                                       
  MT=455 DELAYED NEUTRONS PER FISSION                             
      AVERAGE VALUES OF SYSTEMATICS BY TUTTLE/2/, BENEDETTI ET    
      AL./3/ AND WALDO ET AL./4/  DECAY CONSTANTS WERE ASSUMED    
      TO BE THE SAME AS THOSE OF TH-229 EVALUATED BY BRADY AND    
      ENGLAND/5/.                                                 
  MT=456 PROMPT NEUTRONS PER FISSION                              
      BASED ON THE SEMI-EMPIRICAL FORMULA OF HOWERTON /6/.        
                                                                  
MF=2  RESONANCE PARAMETERS                                        
  MT=151  RESOLVED RESONANCES                                     
      RESONANCE REGION IS BELOW 7.798 EV.  PARAMETERS WERE GIVEN  
      FOR THE MLBW FORMULA.  ONLY TWO RESONANCES WERE OBSERVED BY 
      SIMPSON ET AL./7/.  AN ADDITIONAL TERM WITH 1/V DEPENDENCE  
      WAS ASSUMED TO REPRODUCE THE THERMAL CAPTURE CROSS SECTION. 
      FISSION CROSS SECTION WAS ALSO ASSUMED TO HAVE 1/V BEHAVIOR.
                                                                  
      CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEG.(BARNS)   
                         2200-M/S       RES. INTEG.               
              ELASTIC      12.81           -                      
              CAPTURE     119.9          1170                     
              FISSION       0.300           1.02                  
              TOTAL       133.0             -                     
                                                                  
MF=3  NEUTRON CROSS SECTIONS                                      
      BELOW 7.798 EV IS THE RESONANCE REGION.  BACKGROUND DATA    
      WERE GIVEN.  THE CROSS SECTIONS WERE EVALUATED IN THE ENERGY
      REGION ABOVE 7.798 EV AS FOLLOWS.                           
  MT=1    TOTAL CROSS SECTION                                     
      OPTICAL MODEL CALCULATION WITH THE FOLLOWING PARAMETERS:    
         V  = 41.0 - 0.05*E      (MEV),                           
         WS = 6.4 + 0.15*SQRT(E) (MEV),  -- DER. WOODS-SAXON --   
         VSO= 7.0                (MEV),                           
         R0 = RSO = 1.31         (FM),                            
         RS = 1.38               (FM),                            
         A  = B  = ASO= 0.47     (FM).                            
      THESE PARAMETERS WERE TAKEN FROM THOSE FOR TH-232 /8/.      
  MT=2    ELASTIC SCATTERING CROSS SECTION                        
      BASED ON STATISTICAL AND OPTICAL MODEL CALCULATIONS USING   
      THE CODE CASTHY /9/.                                        
  MT=4,51-62,91  INELASTIC SCATTERING CROSS SECTION               
      STATISTICAL AND OPTICAL MODEL CALCULATIONS.                 
                                                                  
          LEVEL SCHEME OF TH-228 /10/.                            
             NO.      ENERGY(MEV)  SPIN-PARITY                    
              G.S.    0.0           0 +                           
              1       0.0576        2 +                           
              2       0.1869        4 +                           
              3       0.328         1 -                           
              4       0.3961        3 -                           
              5       0.5193        5 -                           
              6       0.8317        0 -                           
              7       0.8746        2 +                           
              8       0.9441        2 +                           
              9       0.952         1 -                           
             10       0.9688        2 +                           
             11       1.016         3 -                           
             12       1.0224        3 +                           
          LEVELS ABOVE 1.025 MEV WERE ASSUMED TO BE OVERLAPPING.  
                                                                  
  MT=16,17  (N,2N) AND (N,3N) CROSS SECTIONS                      
      CALCULATED BY MEANS OF THE EVAPORATION MODEL OF SEGEV AND   
      CANER /11/.                                                 
  MT=18   FISSION CROSS SECTION                                   
      THE DATA OF VOROTNIKOV ET AL./12/ WERE ADOPTED UP TO 5 MEV. 
      THE FISSION CROSS SECTION OF THE NEIGHBORING EVEN-EVEN      
      ISOTOPE TH-230 NORMALIZED TO JOIN SMOOTHLY TO THE DATA OF   
      VOROTNIKOV ET AL. WAS ADOPTED ABOVE 5 MEV.                  
  MT=102  CAPTURE CROSS SECTION                                   
      STATISTICAL AND OPTICAL MODEL CALCULATIONS WITH GAMMA-RAY   
      STRENGTH FUNCTION OF 0.00791.                               
  MT=251  MU-BAR                                                  
      CALCULATED WITH OPTICAL MODEL.                              
                                                                  
MF=4  ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS                 
  MT=2,51-62,91                                                   
      STATISTICAL AND OPTICAL MODEL CALCULATIONS.                 
  MT=16,17,18                                                     
      ASSUMED TO BE ISOTROPIC IN THE LABORATORY SYSTEM.           
                                                                  
MF=5  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS                  
  MT=16,17,91                                                     
      EVAPORATION SPECTRA                                         
  MT=18                                                           
      FISSION SPECTRUM ESTIMATED FROM Z**2/A SYSTEMATICS BY SMITH 
      ET AL./13/.                                                 
                                                                  
REFERENCES                                                        
 1) OHSAWA T. AND OHTA M.: MEMOIRS FACULTY OF ENGINEERING,        
    KYUSHU UNIV. 40, 149 (1980).                                  
 2) TUTTLE R.J.: INDC(NDS)-107/G+SPECIAL, P.29 (1979),            
 3) BENEDETTI G. ET AL.: NUCL. SCI. ENG., 80, 379 (1982).         
 4) WALDO R. ET AL.: PHYS. REV., C23, 1113 (1981).                
 5) BRADY M.C. AND ENGLAND T.R.: NUCL. SCI. ENG., 103, 129(1989). 
 6) HOWERTON R.J.: NUCL. SCI. ENG. 62, 438 (1977).                
 7) SIMPSON O.D. ET AL.: IBID. 29, 423 (1967).                    
 8) OHSAWA T. AND OHTA M.: J. NUCL. SCI. TECHNOL. 18, 408 (1981). 
 9) IGARASI S. AND FUKAHORI T.: JAERI 1321 (1991).                
10) LEDERER C.M. AND SHIRLY V.S. (ED.): TABLE OF ISOTOPES,        
    7TH EDITION (1978).                                           
11) SEGEV M. AND CANER M.: ANN. NUCL. ENERGY 5, 239 (1978).       
12) VOROTNIKOV ET AL.: SOV. J. NUCL. PHYS. 16, 505 (1973).        
13) SMITH A.B. ET AL.: ANL/NDM-50 (1979).