42-Mo- 98

 42-MO- 98 JNDC       EVAL-AUG89 JNDC FP NUCLEAR DATA W.G.        
                      DIST-MAR02 REV4-SEP01            20010904   
----JENDL-3.3         MATERIAL 4243                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
HISTORY                                                           
84-10 Evaluation for JENDL-2 was made by JNDC FPND W.G./1/        
89-08 Modification for JENDL-3 was made/2/.                       
90-02 (n,alpha) cross section was modified.                       
90-10 mf=5: Spectra at threshold energies were modified.          
93-10 JENDL-3.2.                                                  
      Compiled by T.Nakagawa (ndc/jaeri)                          
                                                                  
     *****   modified parts for JENDL-3.2   ********************  
      (2,151)       Unresolved resonance parameters               
      (3,1)         Calculated from new optical potential         
      (3,4), (3,51-91), (3,16), (3,17), (3,22), (3,28)            
                    Taken from JENDL fusion file                  
      (3,32)        Deleted                                       
      (4,16-91)     Taken from JENDL fusion file                  
      (5,16-91)     Taken from JENDL fusion file                  
     ***********************************************************  
                                                                  
     -------------------------------------------------------------
      JENDL fusion file /3/  (as of Oct. 1993)                    
        Evaluated by K.Kosako(nedac) and S.Chiba (ndc/jaeri)      
        Compiled by K.Kosako                                      
                                                                  
          The inelastic scattering, (n,2n), (n,3n), (n,np), (n,na)
        cross sections were calculated with sincros-ii system /4/.
        the other cross sections were taken from JENDL-3.1.  mf=6 
        of mt=16, 17, 22, 28 and 91 were created with f15tob      
        program /3/ in which Kumabe's systematics /5/ was used.   
        the precompound/compound ratio was calculated by the      
        sincros-ii code system/4/.                                
          Optical-model, level density and other parameters used  
        in the sincros-ii calculation are described in ref./4/.   
        Level schemes were determined on the basis of ENSDF/6/.   
     -------------------------------------------------------------
01-08 Compiled by K.Shibata (ndc/jaeri) for JENDL-3.3.            
      *****   modified parts for JENDL-3.3   *********************
      (1,451)         Updated.                                    
      (3.1)           Revised.                                    
      (3,2)           Re-calculated.                              
      (3,4)           Re-calculated.                              
      (3,51:54)       Revised.                                    
      (3,203-207)     Added.                                      
      (3,251)         Deleted.                                    
      (4,2)           Transformation matrix deleted.              
      (4,16-91)       Deleted.                                    
      (5,16-91)       Deleted.                                    
      (6,16-91)       Taken from JENDL fusion file.               
      (12,102)        Added.                                      
      (13,3)          Added.                                      
      (14,3),(14,102) Added.                                      
      (15,3),(15,102) Added.                                      
      ************************************************************
                                                                  
                                                                  
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 32 keV         
    Parameters were taken from JENDL-2 which was evaluated by     
    Kikuchi et al./7/ on the basis of the following experimental  
    data.                                                         
       transmission : Chrien et al./8/                            
       capture      : Weigmann et al./9/, Musgrove et al./10/     
    Average radiation widths of 0.085 eV and 0.12 eV were adopted 
    to s-wave and p-wave resonances, respectively.  A negative    
    resonance was added at -980 eV so as to reproduce the thermal 
    capture cross section given in ref./11/.  Scattering radius   
    was taken from the compilation by Mughabghab et al./11/       
                                                                  
  Unresolved resonance region : 32 keV - 100 keV                  
    The neutron strength functions, S0, S1 and S2 were calculated 
    with optical model code casthy/12/.  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.                                                      
                                                                  
  Typical values of the parameters at 70 keV:                     
    S0 = 0.370e-4, S1 = 5.48e-4, S2 = 0.365e-4, Sg = 1.74e-4,     
    Gg = 0.133 eV, R  = 6.631 fm.                                 
                                                                  
  calculated 2200-m/s cross sections and res. integrals (barns)   
                     2200 m/s               res. integ.           
      total           5.772                    -                  
      elastic         5.642                    -                  
      capture         0.1300                    6.56              
                                                                  
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/13/ standing on a preequilibrium and multi-step    
  evaporation model.  The omp's for neutron given in Table 1(a)   
  were determined by Iijima and Kawai/14/ to reproduce a systema- 
  tic trend of the total cross section.  This set was used for    
  calculation of the capture cross section with casthy and the    
  pegasus calculation, and angular distributions of elastically   
  scattered neutrons.  Another set of parameters in Table 1(b) was
  detemined by Watanabe/15/ to fit better the measued total cross 
  section, and was used for the total cross section calculation   
  for JENDL-3.2.  The omp's for charged particles are as follows: 
     proton   = Perey/16/                                         
     alpha    = Huizenga and Igo/17/                              
     deuteron = Lohr and Haeberli/18/                             
     helium-3 and triton = Becchetti and Greenlees/19/            
  Parameters for the composite level density formula of Gilbert   
  and Cameron/20/ were evaluated by Iijima et al./21/  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
  /22/.                                                           
                                                                  
     For JENDL-3.2, the inelastic scattering, (n,2n), (n,3n),     
  (n,np), (n,na) cross sections were adopted from JENDL fusion    
  file.  The calculation was made with sincros-ii system/4/ by    
  adoptig walter-guss omp modified by Yamamuro/4/ for neutrons,   
  Lemos omp modified by Arthur and Young/23/ for alpha, the same  
  omp's as the pegasus calculation for other charged particles and
  standard level density parameters of sincros-ii system.         
                                                                  
  mt = 1  Total                                                   
    Below 500 keV, spherical optical model calculation was        
    adopted.  Omp in Table 1(a) and casthy were used.  Above 500  
    keV, spline-fitting to the elemental data measured by Foster  
    and Glasgow/29/, Lambropoulos et al./30/ and Poenitz and      
    Whalen /31/ was made.                                         
                                                                  
  mt = 2  Elastic scattering                                      
    Calculated as (total - sum of partial cross sections).        
                                                                  
  mt = 4, 51 - 91  Inelastic scattering                           
    Taken from JENDL fusion file.  The level scheme was taken from
    ref./6/  cntributions of the direct process was calculated for
    the levels marked with '*'.                                   
                                                                  
           no.      energy(MeV)    spin-parity (direct process)   
           gr.       0.0             0  +                         
            1        0.7348          0  +                         
            2        0.7874          2  +          *              
            3        1.4323          2  +                         
            4        1.5100          4  +                         
            5        1.7585          2  +                         
            6        1.8809          4  +                         
            7        1.9650          4  +                         
            8        2.0175          3  -          *              
            9        2.0376          0  +                         
           10        2.1048          2  +                         
           11        2.2063          2  +                         
           12        2.2238          4  +                         
           13        2.3334          2  +          *              
           14        2.3436          6  +                         
      Levels above 2.344 MeV were assumed to be overlapping.      
                                                                  
      For JENDL-3.3, the cross sections for mt=51 to 54 were      
      revised by using Kawano's evaluation /32/.                  
                                                                  
  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                                  
    Adopted from JENDL fusion file.                               
                                                                  
  mt = 102  Capture                                               
    Spherical optical and statistical model calculation with      
    casthy was adopted.  Optical potential parameters are listed  
    in table 1(a).  Direct and semi-direct capture cross sections 
    were estimated according to the procedure of Benzi and        
    Reffo/24/ and normalized to 1 milli-barn at 14 MeV.           
                                                                  
    The gamma-ray strength function (1.62e-04) was adjusted to    
    reproduce the capture cross section measured by Musgrove et   
    al./10/                                                       
                                                                  
  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 (=77.4 ) was estimated by the formula
    derived from Kikuchi-Kawai's formalism/25/ 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)          5.80  mb (measured by Ikeda et al./26/)      
      (n,alpha)      5.70  mb (measured by Ikeda et al.)          
    The (n,alpha) cross section was modified a little by eye-     
    guiding the experimental data of Rahman et al./27/ and of     
    Ikeda et al./26/                                              
                                                                  
  mt=203  Total proton production                                 
    Sum of mt=28 and 103.                                         
                                                                  
  mt=204  Total deuteron production                               
    Equal to mt=104.                                              
                                                                  
  mt=205  Total triton production                                 
    Equal to mt=105.                                              
                                                                  
  mt=207  Total alpha production                                  
    Sum of mt=22 and 107.                                         
                                                                  
mf = 4  Angular distributions of secondary neutrons               
  mt = 2                                                          
    Calculated with casthy/12/ and omp in table 1(a).             
  mt = 51-64                                                      
    Taken from JENDL fusion file data which was calculated with   
    casthy and dwuck/28/ in the sincros-ii system.                
                                                                  
mf = 6  Energy-angle distributions of secondary particles         
  mt = 16,17,22,28,91                                             
    Based on Kumabe's systematics/5/.                             
  mt = 203,204,205,207                                            
    Based on Kalbach's systematics/33/.                           
                                                                  
mf =12  Photon production multiplicities                          
  mt = 102 (below 420 keV)                                        
    Calcuated with casthy.                                        
                                                                  
mf =13  Photon production cross sections                          
  mt = 3 (above 420 keV)                                          
    Fitted with the empirical formula by Howerton and Plechaty    
    /34/ based on the experimental data/35/.                      
                                                                  
mf =14  Photon angular distributions                              
  mt = 3,102                                                      
    Assumed to be isotropic.                                      
                                                                  
mf =15  Continuous photon energy spectra                          
  mt = 3                                                          
    Fitted with the empirical formula by Howerton and Plechaty    
    /34/ based on the experimental data/35/, and compared with    
    experimental data measured by Yamamuro et al./36/.            
  mt = 102                                                        
    Calculated with casthy/12/.                                   
                                                                  
 *Note that gamma-ray produciton for mt=3 was made so as to       
  reproduce measured elemental data.                              
                                                                  
                                                                  
================================================================= 
<> 
================================================================= 
                                                                  
Table 1(a)  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 1(b)  Neutron optical potential parameters                  
                                                                  
                depth (MeV)       radius(fm)*   diffuseness(fm)   
         ----------------------   ------------  ---------------   
        V  = 49.29-0.5266E        r0 = 1.270    a0 = 0.664        
        Ws = 6.574+0.5038E        rs = 1.264    as = 0.538        
        Vso= 9.0                  rso= 1.201    aso= 0.367        
                                   * coefficients of A**(1/3)     
  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    
 ---------------------------------------------------------------  
 40-Zr- 94     1.275e+01 7.530e-01 4.411e-01 7.019e+00 2.320e+00  
 40-Zr- 95     1.331e+01 6.070e-01 5.453e-01 3.985e+00 1.200e+00  
 40-Zr- 96     1.320e+01 7.000e-01 2.235e-01 6.589e+00 2.490e+00  
 40-Zr- 97     1.259e+01 5.590e-01 2.497e-01 3.084e+00 1.200e+00  
                                                                  
 41-Nb- 95     1.277e+01 7.500e-01 2.121e+00 5.782e+00 1.120e+00  
 41-Nb- 96     1.331e+01 5.880e-01 3.406e+00 2.530e+00 0.0        
 41-Nb- 97     1.337e+01 6.710e-01 9.771e-01 5.026e+00 1.290e+00  
 41-Nb- 98     1.380e+01 5.110e-01 2.350e+00 1.731e+00 0.0        
                                                                  
 42-Mo- 96     1.403e+01 7.410e-01 6.991e-01 7.645e+00 2.400e+00  
 42-Mo- 97     1.517e+01 6.800e-01 2.769e+00 6.036e+00 1.280e+00  
 42-Mo- 98     1.594e+01 6.900e-01 7.358e-01 7.888e+00 2.570e+00  
 42-Mo- 99     1.774e+01 6.200e-01 4.294e+00 6.058e+00 1.280e+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 5.291 for Mo- 98 and 2.875 for Mo- 99.             
                                                                  
References                                                        
 1) Aoki, T. et al.: Proc. Int. Conf. on Nuclear Data for Basic   
    and Applied Science, Santa Fe., Vol. 2, p.1627 (1985).        
 2) Kawai, M. et al.: J. Nucl. Sci. Technol., 29, 195 (1992).     
 3) Chiba, S. et al.: JAERI-M 92-027, p.35 (1992).                
 4) Yamamuro, N.: JAERI-M 90-006 (1990).                          
 5) Kumabe, I. et al.: Nucl. Sci. Eng., 104, 280 (1990).          
 6) ENSDF: Evaluated Nuclear Structure Data File, BNL/NNDC.       
 7) Kikuchi, Y. et al.: JAERI-M 86-030 (1986).                    
 8) Chrien, R.E. et al.: Phys. Rev., C13, 578 (1976).             
 9) Weigmann, H. et al.: 1971 Knoxville, 749 (1971).              
10) Musgrove A.R.de L. et al.: Nucl. Phys., A270, 108 (1976).     
11) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. i,     
    Part A", Academic Press (1981).                               
12) Igarasi, S. and Fukahori, T.: JAERI 1321 (1991).              
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    (1983).                                                       
15) Watanabe, T.: Privale communication (1993).                   
16) Perey, F.G: Phys. Rev. 131, 745 (1963).                       
17) Huizenga, J.R. and Igo, G.: Nucl. Phys. 29, 462 (1962).       
18) Lohr, J.M. and Haeberli, W.: Nucl. Phys. A232, 381 (1974).    
19) 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).                                                       
20) Gilbert, A. and Cameron, A.G.W.: Can. J. Phys., 43, 1446      
    (1965).                                                       
21) Iijima, S., et al.: J. Nucl. Sci. Technol. 21, 10 (1984).     
22) Gruppelaar, H.: ECN-13 (1977).                                
23) Arthur, E.D. and Young, P.G.: LA-8626-MS (1980).              
24) Benzi, V. and Reffo, G.: CCDN-NW/10 (1969).                   
25) Kikuchi, K. and Kawai, M.: "Nuclear Matter and Nuclear        
    Reactions", North Holland (1968).                             
26) Ikeda, Y. et al.: JAERI 1312 (1988).                          
27) Rahman, M.M., et al.: Nucl. Phys., A435, 43 (1985).           
28) Kunz, P.D.: Private communication.                            
29) Foster, Jr.D.G. and Glasgow, D.W.: Phys. Rev., C3, 576 (1971).
30) Lambropoulos, P. et al.: Nucl. Phys., A201, 1 (1973).         
31) Poenitz, W.P. and Whalen, J.F.; ANL/NDM-80 (1983).            
32) Kawano, T.: Private communication (2000).                     
33) Kalbach, C. : Phys. Rev. C37, 2350(1988).                     
34) Howerton, S.T. and Plechaty, E.F.: Nucl. Sci. Eng., 32, 178   
    (1968).                                                       
35) Morgan, G. and Newman, N.: ORNL-TM-5097 (1975).               
36) Yamamuro, N. et al.: 1982 Antwerp, 152 (1982).