34-Se- 82

 34-SE- 82 JNDC       EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.        
                      DIST-NOV90                                  
----JENDL-3.2         MATERIAL 3449                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
HISTORY                                                           
90-03 NEW EVALUATION FOR JENDL-3 WAS COMPLETED BY JNDC FPND       
      W.G./1/                                                     
                                                                  
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 18 KEV         
    RESONANCE ENERGIES WERE BASED ON THE EXPERIMENTAL DATA BY     
    BROWNE AND BERMAN/2/.  THE VALUES OF NEUTRON ORBITAL ANGULAR  
    MOMENTUM L AND TOTAL SPIN J WERE ASSUMED TO BE 0 AND 0.5 FOR  
    ALL RESONANCE LEVELS, RESPECTIVELY.                           
                                                                  
    REDUCED NEUTRON WIDTH OF EACH RESONANCE LEVEL WAS ROUGHLY     
    ESTIMATED ON THE BASIS OF THE DESCRIPTION FOR RESONANCE       
    STRUCTURES GIVEN BY BROWNE AND BERMAN, AND OF THE REDUCED     
    NEUTRON WIDTHS GIVEN BY MUGHABGHAB ET AL./3/ IN THE FIRST     
    STAGE.  NEXT, THERMAL SCATTERING CROSS SECTION WAS CALCULATED 
    USING THE ROUGHLY ESTIMATED REDUCED NEUTRON WIDTHS, AND A     
    NORMALIZATION FACTOR WAS OBTAINED SO AS TO REPRODUCE THE      
    EXPERIMENTAL DATA OF 5.0+-0.2 BARNS GIVEN BY MUGHABGHAB ET AL.
    THE FINAL NEUTRON WIDTHS WERE DETERMINED BY USING THIS        
    NORMALIZATION FACTOR AND THE RESONANCE ENERGIES GIVEN BY      
    BROWNE AND BERMAN.                                            
                                                                  
    SCATTERING RADIUS WAS TAKEN FROM MUGHABGHAB ET AL.  AVERAGE   
    RADIATION WIDTH WAS ALSO DETERMINED SO AS TO REPRODUCE THERMAL
    CAPTURE CROSS SECTION OF 44.2 MB GIVEN BY MUGHABGHAB ET AL.  A
    NEGATIVE RESONANCE WAS ADDED AT -120 EV IN THE PRESENT        
    ANALYSIS.                                                     
                                                                  
  UNRESOLVED RESONANCE REGION : 18 KEV - 100 KEV                  
    THE NEUTRON STRENGTH FUNCTION S0 WAS BASED ON THE COMPILATION 
    OF MUGHABGHAB ET AL., AND S1 WAS BASED ON THE SYSTEMATICS OF  
    MUGHABGHAB ET AL., AND S2 WAS CALCULATED WITH OPTICAL MODEL   
    CODE CASTHY/4/.  THE OBSERVED LEVEL SPACING WERE DETERMINED TO
    REPRODUCE THE CAPTURE CROSS SECTION CALCULATED WITH CASTHY.   
    THE EFFECTIVE SCATTERING RADIUS WAS OBTAINED FROM FITTING TO  
    THE CALCULATED TOTAL CROSS SECTION AT 100 KEV.  THE RADIATION 
    WIDTH GG WAS DETERMINED FROM A SYSTEMATIC TREND OF MEASURED   
    VALUES FOR NEIGHBORING NUCLIDES.                              
                                                                  
  TYPICAL VALUES OF THE PARAMETERS AT 70 KEV:                     
    S0 = 1.210E-4, S1 = 2.100E-4, S2 = 0.680E-4, SG = 0.572E-4,   
    GG = 0.190 EV, R  = 7.074 FM.                                 
                                                                  
  CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEGRALS (BARNS)   
                     2200 M/S               RES. INTEG.           
      TOTAL           5.044                    -                  
      ELASTIC         5.000                    -                  
      CAPTURE         0.04420                   0.799             
                                                                  
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/5/ 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 R0, RS AND RSO OF IIJIMA-KAWAI POTENTIAL/6/.
  THE OMP'S FOR CHARGED PARTICLES ARE AS FOLLOWS:                 
     PROTON   = PEREY/7/                                          
     ALPHA    = HUIZENGA AND IGO/8/                               
     DEUTERON = LOHR AND HAEBERLI/9/                              
     HELIUM-3 AND TRITON = BECCHETTI AND GREENLEES/10/            
  PARAMETERS FOR THE COMPOSITE LEVEL DENSITY FORMULA OF GILBERT   
  AND CAMERON/11/ WERE EVALUATED BY IIJIMA ET AL./12/  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
  /13/.                                                           
                                                                  
  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 BASED ON EVALUATED NUCLEAR      
    STRUCTURE DATA FILE (1987 VERSION)/14/ AND NUCLEAR DATA       
    SHEETS/15/.                                                   
                                                                  
           NO.      ENERGY(MEV)    SPIN-PARITY                    
           GR.       0.0             0  +                         
            1        0.6548          2  +                         
            2        1.4200          0  +                         
            3        1.7312          2  +                         
            4        1.7354          4  +                         
            5        2.5508          3  +                         
            6        2.8942          5  -                         
      LEVELS ABOVE 3.015 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/16/ AND NORMALIZED TO 1 MILLI-BARN AT 14 MEV.       
                                                                  
    THE GAMMA-RAY STRENGTH FUNCTION (5.46E-05) WAS ADJUSTED TO    
    REPRODUCE THE CAPTURE CROSS SECTION OF 0.045 BARN AT 25 KEV   
    WHICH WAS A SOMEWHAT LARGER VALUE THAN A META-STABLE STATE    
    PRODUCTION CROSS SECTION OF 0.045 BARN AT 24 KEV MEASURED BY  
    CHAUBEY AND SEHGAL/17/                                        
                                                                  
  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 =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 (=  96.6) WAS ESTIMATED BY THE       
    FORMULA DERIVED FROM KIKUCHI-KAWAI'S FORMALISM/18/ AND LEVEL  
    DENSITY PARAMETERS.                                           
                                                                  
    FINALLY, THE (N,2N) AND (N,P) CROSS SECTIONS WERE             
    NORMALIZED TO THE FOLLOWING VALUES AT 14.5 MEV:               
      (N,2N)      1100.00  MB (MEASURED BY FREHAUT+/19/)          
      (N,P)          2.40  MB (SYSTEMATICS OF FORREST/20/)        
                                                                  
  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 TO OVERLAPPING LEVELS AND FOR  
  OTHER NEUTRON EMITTING REACTIONS.                               
                                                                  
TABLE 1  NEUTRON OPTICAL POTENTIAL PARAMETERS                     
                                                                  
                DEPTH (MEV)       RADIUS(FM)    DIFFUSENESS(FM)   
         ----------------------   ------------  ---------------   
        V  = 46.0-0.25E           R0 = 5.7      A0 = 0.62         
        WS = 7.0                  RS = 6.2      AS = 0.35         
        VSO= 7.0                  RSO= 5.7      ASO= 0.62         
  THE FORM OF SURFACE ABSORPTION PART IS DER. WOODS-SAXON TYPE.   
                                                                  
TABLE 2  LEVEL DENSITY PARAMETERS                                 
                                                                  
 NUCLIDE  SYST A(1/MEV)  T(MEV)    C(1/MEV)  EX(MEV)   PAIRING    
 ---------------------------------------------------------------  
 32-GE- 78     1.234E+01 8.699E-01 7.304E-01 9.395E+00 2.930E+00  
 32-GE- 79     1.362E+01 7.523E-01 2.737E+00 6.567E+00 1.360E+00  
 32-GE- 80  *  1.277E+01 8.125E-01 5.273E-01 8.551E+00 2.820E+00  
 32-GE- 81  *  1.255E+01 8.025E-01 2.496E+00 6.770E+00 1.360E+00  
                                                                  
 33-AS- 79     1.290E+01 8.230E-01 3.020E+00 7.585E+00 1.570E+00  
 33-AS- 80     1.150E+01 7.250E-01 4.181E+00 3.535E+00 0.0        
 33-AS- 81  *  1.293E+01 8.025E-01 2.772E+00 7.120E+00 1.460E+00  
 33-AS- 82  *  1.271E+01 7.927E-01 1.371E+01 5.344E+00 0.0        
                                                                  
 34-SE- 80     1.334E+01 8.130E-01 6.129E-01 9.136E+00 3.000E+00  
 34-SE- 81     1.368E+01 7.490E-01 2.463E+00 6.614E+00 1.430E+00  
 34-SE- 82     1.259E+01 7.980E-01 3.563E-01 8.246E+00 2.890E+00  
 34-SE- 83     1.381E+01 7.500E-01 2.666E+00 6.708E+00 1.430E+00  
 ---------------------------------------------------------------  
  SYST:  * = LDP'S WERE DETERMINED FROM SYSTEMATICS.              
                                                                  
 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 6.291 FOR SE- 82 AND 5.0 FOR SE- 83.               
                                                                  
REFERENCES                                                        
 1) KAWAI, M. ET AL.: PROC. INT. CONF. ON NUCLEAR DATA FOR SCIENCE
    AND TECHNOLOGY, MITO, P. 569 (1988).                          
 2) BROWNE,J.C. AND BERMAN, B.L.: PHYS. REV. C26, 969 (1982).     
 3) MUGHABGHAB, S.F. ET AL.: "NEUTRON CROSS SECTIONS, VOL. I,     
    PART A", ACADEMIC PRESS (1981).                               
 4) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975).           
 5) IIJIMA, S. ET AL.: JAERI-M 87-025, P. 337 (1987).             
 6) IIJIMA, S. AND KAWAI, M.: J. NUCL. SCI. TECHNOL., 20, 77      
    (1983).                                                       
 7) PEREY, F.G: PHYS. REV. 131, 745 (1963).                       
 8) HUIZENGA, J.R. AND IGO, G.: NUCL. PHYS. 29, 462 (1962).       
 9) LOHR, J.M. AND HAEBERLI, W.: NUCL. PHYS. A232, 381 (1974).    
10) BECCHETTI, F.D., JR. AND GREENLEES, G.W.: POLARIZATION        
    PHENOMENA IN NUCLEAR REACTIONS ((EDS) H.H. BARSHALL AND       
    W. HAEBERLI), P. 682, THE UNIVERSITY OF WISCONSIN PRESS.      
    (1971).                                                       
11) GILBERT, A. AND CAMERON, A.G.W.: CAN. J. PHYS., 43, 1446      
    (1965).                                                       
12) IIJIMA, S., ET AL.: J. NUCL. SCI. TECHNOL. 21, 10 (1984).     
13) GRUPPELAAR, H.: ECN-13 (1977).                                
14) ENSDF: EVALUATED NUCLEAR STRUCTURE DATA FILE (JUNE 1987).     
15) NUCLEAR DATA SHEETS, 50, 1 (1987).                            
16) BENZI, V. AND REFFO, G.: CCDN-NW/10 (1969).                   
17) CHAUBEY, A.K. AND SEHGAL, M.L.: PHYS. REV., 152, 1055 (1966). 
18) KIKUCHI, K. AND KAWAI, M.: "NUCLEAR MATTER AND NUCLEAR        
    REACTIONS", NORTH HOLLAND (1968).                             
19) FREHAUT, J., ET AL.: SYMP. ON NEUTRON CROSS SECTIONS FROM     
    10-50MEV, BNL, P.399 (1980)                                   
20) FORREST, R.A.: AERE-R 12419 (1986).