56-Ba-137

 56-BA-137 JNDC       EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.        
                      DIST-SEP90 REV2-OCT93                       
----JENDL-3.2         MATERIAL 5646                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
84-10 EVALUATION FOR JENDL-2 WAS MADE BY JNDC FPND W.G./1/        
90-03 MODIFICATION FOR JENDL-3 WAS MADE/2/.                       
93-10 JENDL-3.2 WAS MADE BY JNDC FPND W.G.                        
                                                                  
     *****   MODIFIED PARTS FOR JENDL-3.2   ********************  
      (2,151)       RESOLVED RESONANCE PARAMETERS WERE MODIFIED.  
     ***********************************************************  
                                                                  
                                                                  
MF = 1  GENERAL INFORMATION                                       
  MT=451 COMMENTS AND DICTIONARY                                  
                                                                  
MF = 2  RESONANCE PARAMETERS                                      
  MT=151 RESOLVED AND UNRESOLVED RESONANCE PARAMETERS             
  RESOLVED RESONANCE REGION (MLBW FORMULA) : BELOW 11.885 KEV     
       FOR JENDL-2, EVALUATION WAS MADE BY KIKUCHI/3/.  BELOW 1.7 
    KEV, PARAMETERS WERE DETERMINED FROM THE EXPERIMENTAL DATA OF 
    ALVES ET AL./4/ AND VAN DE VYVER AND PATTENDEN/5/.  AVERAGE   
    RADIATION WIDTHS WERE ASSUMED TO BE 0.08 EV FOR S-WAVE        
    RESONANCES AND 0.068 EV FOR P-WAVE ONES EXCEPT FOR 420- AND   
    578-EV LEVELS.  ABOVE 3 KEV, EVALUATION WAS BASED ON THE DATA 
    OF MUSGROVE ET AL./6/.  MANY ARTIFICIAL LEVELS WERE GENERATED 
    WITH STAT/7/ BY ASSUMING D=380 EV, S0=0.57E-4, S1=0.45E-4.  A 
    NEGATIVE RESONANCE WAS ADDED AT -26 EV SO AS TO REPRODUCE THE 
    CAPTURE CROSS SECTION OF 5.1 +- 0.4 BARNS AT 0.0253 EV/8/.    
       FOR JENDL-3, THE RESONANCE PARAMETERS OF JENDL-2 WERE      
    UPDATED BY USING THE NEWEST EXPERIMENTAL DATA BY MIZUMOTO /9/.
    THE RESONANCE ENERGIES AND NEUTRON WIDTHS WERE REPLACED BY    
    MIZUMOTO'S DATA IN THE ENERGY RANGE FROM 418.3 EV TO 14.941   
    KEV.  AVERAGE RADIATION WIDTH AND SCATTERING RADIUS WERE TAKEN
    FROM MUGHABGHAB ET AL./8/ TOTAL SPIN J OF SOME RESONANCES WAS 
    TENTATIVELY ESTIMATED WITH A RANDOM NUMBER METHOD.            
                                                                  
  UNRESOLVED RESONANCE REGION : 11.885 KEV - 100 KEV              
    INITIAL VALUES OF NEUTRON STRENGTH FUNCTIONS, S0 AND S1, WERE 
    ADOPTED FROM THE RECOMMENDATION BY MUGHABGHAB ET AL., AND S2  
    WAS TAKEN FROM CALCULATION WITH CASTHY/10/.  THE PARAMETERS   
    WERE ADJUSTED TO REPRODUCE THE CAPTURE CROSS SECTION MEASURED 
    BY MUSGROVE ET AL./11/  THE EFFECTIVE SCATTERING RADIUS WAS   
    OBTAINED FROM FITTING TO THE CALCULATED TOTAL CROSS SECTION AT
    100 KEV.  THE RADIATION WIDTH GG WAS ADOPTED FROM REF./8/.    
                                                                  
  TYPICAL VALUES OF THE PARAMETERS AT 70 KEV:                     
    S0 = 0.695E-4, S1 = 0.525E-4, S2 = 0.949E-4, SG = 3.91E-4,    
    GG = 0.080 EV, R  = 5.729 FM.                                 
                                                                  
  CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEGRALS (BARNS)   
                     2200 M/S               RES. INTEG.           
      TOTAL           9.0034                   -                  
      ELASTIC         3.8816                   -                  
      CAPTURE         5.1218                    4.75              
                                                                  
MF = 3  NEUTRON CROSS SECTIONS                                    
  BELOW 100 KEV, RESONANCE PARAMETERS WERE GIVEN.                 
  ABOVE 100 KEV, THE SPHERICAL OPTICAL AND STATISTICAL MODEL      
  CALCULATION WAS PERFORMED WITH CASTHY, BY TAKING ACCOUNT OF     
  COMPETING REACTIONS, OF WHICH CROSS SECTIONS WERE CALCULATED    
  WITH PEGASUS/12/ STANDING ON A PREEQUILIBRIUM AND MULTI-STEP    
  EVAPORATION MODEL.  THE OMP'S FOR NEUTRON GIVEN IN TABLE 1 WERE 
  DETERMINED TO REPRODUCE A SYSTEMATIC TREND OF THE TOTAL CROSS   
  SECTION BY CHANGING WS AND RSO OF IIJIMA-KAWAI POTENTIAL/13/.   
  THE OMP'S FOR CHARGED PARTICLES ARE AS FOLLOWS:                 
     PROTON   = PEREY/14/                                         
     ALPHA    = HUIZENGA AND IGO/15/                              
     DEUTERON = LOHR AND HAEBERLI/16/                             
     HELIUM-3 AND TRITON = BECCHETTI AND GREENLEES/17/            
  PARAMETERS FOR THE COMPOSITE LEVEL DENSITY FORMULA OF GILBERT   
  AND CAMERON/18/ WERE EVALUATED BY IIJIMA ET AL./19/  MORE       
  EXTENSIVE DETERMINATION AND MODIFICATION WERE MADE IN THE       
  PRESENT WORK.  TABLE 2 SHOWS THE LEVEL DENSITY PARAMETERS USED  
  IN THE PRESENT CALCULATION.  ENERGY DEPENDENCE OF SPIN CUT-OFF  
  PARAMETER IN THE ENERGY RANGE BELOW E-JOINT IS DUE TO GRUPPELAAR
  /20/.                                                           
                                                                  
  MT = 1  TOTAL                                                   
    SPHERICAL OPTICAL MODEL CALCULATION WAS ADOPTED.              
                                                                  
  MT = 2  ELASTIC SCATTERING                                      
    CALCULATED AS (TOTAL - SUM OF PARTIAL CROSS SECTIONS).        
                                                                  
  MT = 4, 51 - 91  INELASTIC SCATTERING                           
    SPHERICAL OPTICAL AND STATISTICAL MODEL CALCULATION WAS       
    ADOPTED.  THE LEVEL SCHEME WAS TAKEN FROM REF./21/.           
                                                                  
           NO.      ENERGY(MEV)    SPIN-PARITY                    
           GR.       0.0            3/2 +                         
            1        0.2792         1/2 +                         
            2        0.6616        11/2 -                         
            3        1.2900         5/2 +                         
            4        1.4629         5/2 +                         
            5        1.7900         7/2 -                         
            6        1.8400         1/2 +                         
            7        1.9000         5/2 +                         
            8        2.0400         5/2 +                         
      LEVELS ABOVE 2.12 MEV WERE ASSUMED TO BE OVERLAPPING.       
                                                                  
  MT = 102  CAPTURE                                               
    SPHERICAL OPTICAL AND STATISTICAL MODEL CALCULATION WITH      
    CASTHY WAS ADOPTED.  DIRECT AND SEMI-DIRECT CAPTURE CROSS     
    SECTIONS WERE ESTIMATED ACCORDING TO THE PROCEDURE OF BENZI   
    AND REFFO/22/ AND NORMALIZED TO 1 MILLI-BARN AT 14 MEV.       
                                                                  
    THE GAMMA-RAY STRENGTH FUNCTION (3.65E-04) WAS ADJUSTED TO    
    REPRODUCE THE CAPTURE CROSS SECTION OF 33 MILLI-BARNS AT 100  
    KEV MEASURED BY MUSGROVE ET AL./11/                           
                                                                  
  MT = 16  (N,2N) CROSS SECTION                                   
  MT = 17  (N,3N) CROSS SECTION                                   
  MT = 22  (N,N'A) CROSS SECTION                                  
  MT = 28  (N,N'P) CROSS SECTION                                  
  MT = 32  (N,N'D) CROSS SECTION                                  
  MT =103  (N,P) CROSS SECTION                                    
  MT =104  (N,D) CROSS SECTION                                    
  MT =105  (N,T) CROSS SECTION                                    
  MT =107  (N,ALPHA) CROSS SECTION                                
    THESE REACTION CROSS SECTIONS WERE CALCULATED WITH THE        
    PREEQUILIBRIUM AND MULTI-STEP EVAPORATION MODEL CODE PEGASUS. 
                                                                  
    THE KALBACH'S CONSTANT K (= 435.5) WAS ESTIMATED BY THE       
    FORMULA DERIVED FROM KIKUCHI-KAWAI'S FORMALISM/23/ AND LEVEL  
    DENSITY PARAMETERS.                                           
                                                                  
    FINALLY, THE (N,2N), (N,P) AND (N,ALPHA) CROSS SECTIONS WERE  
    NORMALIZED TO THE FOLLOWING VALUES AT 14.5 MEV:               
      (N,2N)      1710.00  MB (SYSTEMATICS OF WEN DEN LU+/24/)    
      (N,P)          3.32  MB (SYSTEMATICS OF FORREST/25/)        
      (N,ALPHA)      1.59  MB (SYSTEMATICS OF FORREST)            
                                                                  
  MT = 251  MU-BAR                                                
    CALCULATED WITH CASTHY.                                       
                                                                  
MF = 4  ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS               
  LEGENDRE POLYNOMIAL COEFFICIENTS FOR ANGULAR DISTRIBUTIONS ARE  
  GIVEN IN THE CENTER-OF-MASS SYSTEM FOR MT=2 AND DISCRETE INELAS-
  TIC LEVELS, AND IN THE LABORATORY SYSTEM FOR MT=91.  THEY WERE  
  CALCULATED WITH CASTHY.  FOR OTHER REACTIONS, ISOTROPIC DISTRI- 
  BUTIONS IN THE LABORATORY SYSTEM WERE ASSUMED.                  
                                                                  
MF = 5  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS                
  ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS WERE CALCULATED WITH 
  PEGASUS FOR INELASTIC SCATTERING FROM OVERLAPPING LEVELS AND FOR
  OTHER NEUTRON EMITTING REACTIONS.                               
                                                                  
TABLE 1  NEUTRON OPTICAL POTENTIAL PARAMETERS                     
                                                                  
                DEPTH (MEV)       RADIUS(FM)    DIFFUSENESS(FM)   
         ----------------------   ------------  ---------------   
        V  = 41.8                 R0 = 6.89     A0 = 0.62         
        WS = 2.95+0.789E          RS = 7.098    AS = 0.35         
        VSO= 7.0                  RSO= 6.89     ASO= 0.62         
  THE FORM OF SURFACE ABSORPTION PART IS DER. WOODS-SAXON TYPE.   
                                                                  
TABLE 2  LEVEL DENSITY PARAMETERS                                 
                                                                  
 NUCLIDE       A(1/MEV)  T(MEV)    C(1/MEV)  EX(MEV)   PAIRING    
 ---------------------------------------------------------------  
 54-XE-133     1.600E+01 6.250E-01 2.327E+00 5.284E+00 1.120E+00  
 54-XE-134     1.400E+01 6.300E-01 3.184E-01 5.224E+00 1.820E+00  
 54-XE-135     1.550E+01 5.565E-01 7.506E-01 4.010E+00 1.120E+00  
 54-XE-136     1.400E+01 6.500E-01 3.270E-01 5.679E+00 1.970E+00  
                                                                  
 55-CS-134     1.598E+01 6.450E-01 1.710E+01 4.505E+00 0.0        
 55-CS-135     1.343E+01 6.537E-01 1.831E+00 4.203E+00 7.000E-01  
 55-CS-136     1.400E+01 6.000E-01 4.424E+00 2.967E+00 0.0        
 55-CS-137     1.336E+01 6.200E-01 9.986E-01 3.836E+00 8.500E-01  
                                                                  
 56-BA-135     1.902E+01 5.820E-01 2.277E+00 6.108E+00 1.580E+00  
 56-BA-136     1.610E+01 6.500E-01 5.721E-01 6.928E+00 2.280E+00  
 56-BA-137     1.645E+01 5.640E-01 5.394E-01 4.905E+00 1.580E+00  
 56-BA-138     1.390E+01 7.200E-01 4.123E-01 7.233E+00 2.430E+00  
 ---------------------------------------------------------------  
                                                                  
 SPIN CUTOFF PARAMETERS WERE CALCULATED AS 0.146*SQRT(A)*A**(2/3).
 IN THE CASTHY CALCULATION, SPIN CUTOFF FACTORS AT 0 MEV WERE     
 ASSUMED TO BE 5.625 FOR BA-137 AND 7.914 FOR BA-138.             
                                                                  
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    (1971).                                                       
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    REACTIONS", NORTH HOLLAND (1968).                             
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