41-Nb- 94

 41-NB- 94 JNDC       EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.        
                      DIST-NOV90                                  
----JENDL-3.2         MATERIAL 4128                               
-----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 0.028 KEV      
    PARAMETERS WERE TAKEN FROM THE COMPILATION OF MUGHABGHAB ET   
    AL./2/  TOTAL SPIN J OF SOME RESONANCES WAS TENTATIVELY       
    ESTIMATED WITH A RANDOM NUMBER METHOD.  A NEGATIVE RESONANCE  
    WAS ADDED SO AS TO REPRODUCE THE THERMAL CAPTURE CROSS SECTION
    (15.5 BARNS) GIVEN BY MUGHABGHAB ET AL./2/  SCATTERING RADIUS 
    WAS ASSUMED TO BE 7.0 FM ACCORDING TO THE SYSTEMATICS OF      
    MEASURED VALUES.                                              
                                                                  
  UNRESOLVED RESONANCE REGION : 0.028 KEV - 100 KEV               
    THE NEUTRON STRENGTH FUNCTIONS, S0, S1 AND S2 WERE CALCULATED 
    WITH OPTICAL MODEL CODE CASTHY/3/.  THE OBSERVED LEVEL SPACING
    WAS 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 WAS TAKEN FROM THE COMPILATION  
    OF MUGHABGHAB ET AL.                                          
                                                                  
  TYPICAL VALUES OF THE PARAMETERS AT 70 KEV:                     
    S0 = 0.400E-4, S1 = 5.500E-4, S2 = 0.400E-4, SG = 25.2E-4,    
    GG = 0.188 EV, R  = 6.696 FM.                                 
                                                                  
  CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEGRALS (BARNS)   
                     2200 M/S               RES. INTEG.           
      TOTAL          22.22                     -                  
      ELASTIC         6.453                    -                  
      CAPTURE        15.77                    126                 
                                                                  
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/4/ STANDING ON A PREEQUILIBRIUM AND MULTI-STEP     
  EVAPORATION MODEL.  THE OMP'S FOR NEUTRON GIVEN IN TABLE 1 WERE 
  DETERMINED BY IIJIMA AND KAWAI/5/ TO REPRODUCE A SYSTEMATIC     
  TREND OF THE TOTAL CROSS SECTION.  THE OMP'S FOR CHARGED        
  PARTICLES ARE AS FOLLOWS:                                       
     PROTON   = PEREY/6/                                          
     ALPHA    = HUIZENGA AND IGO/7/                               
     DEUTERON = LOHR AND HAEBERLI/8/                              
     HELIUM-3 AND TRITON = BECCHETTI AND GREENLEES/9/             
  PARAMETERS FOR THE COMPOSITE LEVEL DENSITY FORMULA OF GILBERT   
  AND CAMERON/10/ WERE EVALUATED BY IIJIMA ET AL./11/  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
  /12/.                                                           
                                                                  
  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)/13/ AND NUCLEAR DATA       
    SHEETS/14/.                                                   
                                                                  
           NO.      ENERGY(MEV)    SPIN-PARITY                    
           GR.       0.0             6  +                         
            1        0.0410          3  +                         
            2        0.0587          4  +                         
            3        0.0787          7  +                         
            4        0.1134          5  +                         
            5        0.1403          2  -                         
            6        0.3016          2  -                         
            7        0.3119          4  +                         
            8        0.3342          3  +                         
            9        0.3963          3  -                         
           10        0.4502          3  -                         
           11        0.6317          4  +                         
           12        0.6409          5  +                         
           13        0.6657          3  +                         
           14        0.7849          3  +                         
           15        0.7929          3  -                         
           16        0.8178          3  -                         
           17        0.8957          3  +                         
           18        0.9240          2  +                         
           19        0.9352          0  +                         
           20        0.9586          5  +                         
           21        0.9790          2  -                         
           22        1.0077          4  +                         
           23        1.0612          4  +                         
           24        1.0857          2  +                         
           25        1.1633          3  +                         
           26        1.1707          4  +                         
           27        1.2020          0  +                         
           28        1.2327          2  +                         
           29        1.2569          0  +                         
      LEVELS ABOVE 1.264 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/15/ AND NORMALIZED TO 1 MILLI-BARN AT 14 MEV.       
                                                                  
    THE GAMMA-RAY STRENGTH FUNCTION (2.53E-03) WAS DETERMINED FROM
    THE SYSTEMATICS OF RADIATION WIDTH (0.188 EV) AND THE AVERAGE 
    S-WAVE RESONANCE LEVEL SPACING (74.4 EV) CALCULATED FROM THE  
    LEVEL DENSITY PARAMETERS.                                     
                                                                  
  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 = 33  (N,N'T) CROSS SECTION                                  
  MT =103  (N,P) CROSS SECTION                                    
  MT =104  (N,D) CROSS SECTION                                    
  MT =105  (N,T) CROSS SECTION                                    
  MT =106  (N,HE3) 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 (= 183.2) WAS ESTIMATED BY THE       
    FORMULA DERIVED FROM KIKUCHI-KAWAI'S FORMALISM/16/ AND LEVEL  
    DENSITY PARAMETERS.                                           
                                                                  
    FINALLY, THE (N,P) AND (N,ALPHA) CROSS SECTIONS WERE          
    NORMALIZED TO THE FOLLOWING VALUES AT 14.5 MEV:               
      (N,P)         22.20  MB (SYSTEMATICS OF FORREST/17/)        
      (N,ALPHA)      6.42  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 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 = 5.893    A0 = 0.62         
        WS = 7.0                  RS = 6.393    AS = 0.35         
        VSO= 7.0                  RSO= 5.893    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    
 ---------------------------------------------------------------  
 39-Y - 90     1.027E+01 6.770E-01 1.716E+00 2.209E+00 0.0        
 39-Y - 91     1.050E+01 7.140E-01 8.362E-01 3.521E+00 7.200E-01  
 39-Y - 92     1.012E+01 7.629E-01 2.480E+00 3.191E+00 0.0        
 39-Y - 93     1.150E+01 8.053E-01 1.740E+00 5.854E+00 1.120E+00  
                                                                  
 40-ZR- 91     1.036E+01 8.000E-01 7.822E-01 5.057E+00 1.200E+00  
 40-ZR- 92     1.088E+01 8.192E-01 5.122E-01 6.429E+00 1.920E+00  
 40-ZR- 93     1.298E+01 7.000E-01 1.273E+00 5.183E+00 1.200E+00  
 40-ZR- 94     1.275E+01 7.530E-01 4.411E-01 7.019E+00 2.320E+00  
                                                                  
 41-NB- 92     1.040E+01 8.410E-01 4.607E+00 4.477E+00 0.0        
 41-NB- 93     1.250E+01 7.120E-01 2.205E+00 4.629E+00 7.200E-01  
 41-NB- 94     1.281E+01 7.230E-01 7.763E+00 4.250E+00 0.0        
 41-NB- 95     1.277E+01 7.500E-01 2.121E+00 5.782E+00 1.120E+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 7.400 FOR NB- 94 AND 3.625 FOR NB- 95.             
                                                                  
REFERENCES                                                        
 1) KAWAI, M. ET AL.: PROC. INT. CONF. ON NUCLEAR DATA FOR SCIENCE
    AND TECHNOLOGY, MITO, P. 569 (1988).                          
 2) MUGHABGHAB, S.F. ET AL.: "NEUTRON CROSS SECTIONS, VOL. I,     
    PART A", ACADEMIC PRESS (1981).                               
 3) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975).           
 4) IIJIMA, S. ET AL.: JAERI-M 87-025, P. 337 (1987).             
 5) IIJIMA, S. AND KAWAI, M.: J. NUCL. SCI. TECHNOL., 20, 77      
    (1983).                                                       
 6) PEREY, F.G: PHYS. REV. 131, 745 (1963).                       
 7) HUIZENGA, J.R. AND IGO, G.: NUCL. PHYS. 29, 462 (1962).       
 8) LOHR, J.M. AND HAEBERLI, W.: NUCL. PHYS. A232, 381 (1974).    
 9) 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).                                                       
10) GILBERT, A. AND CAMERON, A.G.W.: CAN. J. PHYS., 43, 1446      
    (1965).                                                       
11) IIJIMA, S., ET AL.: J. NUCL. SCI. TECHNOL. 21, 10 (1984).     
12) GRUPPELAAR, H.: ECN-13 (1977).                                
13) ENSDF: EVALUATED NUCLEAR STRUCTURE DATA FILE (JUNE 1987).     
14) NUCLEAR DATA SHEETS, 44, 277 (1985).                          
15) BENZI, V. AND REFFO, G.: CCDN-NW/10 (1969).                   
16) KIKUCHI, K. AND KAWAI, M.: "NUCLEAR MATTER AND NUCLEAR        
    REACTIONS", NORTH HOLLAND (1968).                             
17) FORREST, R.A.: AERE-R 12419 (1986).