96-Cm-244

 96-Cm-244 JAEA+      EVAL-JAN10 O.Iwamoto,T.Nakagawa,T.Ohsawa+   
                      DIST-MAY10                       20100318   
----JENDL-4.0         MATERIAL 9637                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
History                                                           
06-03 Fission cross section was evaluated with GMA.               
06-04 Resonance parameters were modified.                         
07-03 Fission spectra were evaluated.                             
07-05 New calculation was made with CCONE code.                   
07-07 Nu-p was revised.                                           
07-10 Nu-p was revised.                                           
07-12 Parameters of negative and 1st resonances were modified.    
08-03 Interpolation of (5,18) was changed.                        
      Data were compiled as JENDL/AC-2008/1/.                     
09-03 (1,452) and (1,455) were revised.                           
09-08 (MF1,MT458) was evaluated.                                  
10-01 Data of prompt gamma rays due to fission were given.        
10-03 Covariance data were given.                                 
                                                                  
                                                                  
MF= 1 General information                                         
  MT=452 Number of Neutrons per fission                           
    Sum of MT's=455 and 456.                                      
                                                                  
  MT=455 Delayed neutron data                                     
    Determined from nu-d of the following three nuclides and      
    partial fission cross sections calculated with CCONE code/2/. 
                                                                  
      Cm-245 = 0.004451                                           
      Cm-244 = 0.003064                                           
      Cm-243 = 0.002114                                           
                They are averages of systematics by Tuttle/3/,    
                Benedetti et al./4/ and Waldo et al./5/           
                                                                  
                                                                  
  MT=456 Number of prompt neutrons per fission                    
    The experimental data of 2.75+-0.08 measured by Zhuravlev et  
    al./6/ seems to be too small. A value of 3.00 at 0 eV         
    was assumed. An energy dependent term was based on the        
    systematics derived by Ohsawa/7/.                             
                                                                  
  MT=458 Components of energy release due to fission              
    Total energy and prompt energy were calculated from mass      
    balance using JENDL-4 fission yields data and mass excess     
    evaluation. Mass excess values were from Audi's 2009          
    evaluation/8/. Delayed energy values were calculated from     
    the energy release for infinite irradiation using JENDL FP    
    Decay Data File 2000 and JENDL-4 yields data. For delayed     
    neutron energy, as the JENDL FP Decay Data File 2000/9/ does  
    not include average neutron energy values, the average values 
    were calculated using the formula shown in the report by      
    T.R. England/10/. The fractions of prompt energy were         
    calculated using the fractions of Sher's evaluation/11/ when  
    they were provided. When the fractions were not given by Sher,
    averaged fractions were used.                                 
                                                                  
                                                                  
MF= 2 Resonance parameters                                        
  MT=151                                                          
  Resolved resonance parameters (MLBW: 1.0E-5 - 1000eV)           
    Resonance parameters given in JENDL-3.3 were based on the     
    data of Belanova et al./12/, Moore and Keyworth/13/ and       
    Maguire et al./14/                                            
                                                                  
    In the present work, negative and first resonances were       
    modified so as to reproduce thermal cross sections and        
    resonance integral. Background was given to the fission       
    cross section.                                                
                                                                  
    The thermal cross sections to be reproduced:                  
      Total   = 27.6 +- 1.4 b /15/                                
      Elastic = 11.6 +- 0.7 b /15/                                
      Fission = 1.02 +- 0.19 b                                    
         Benjamin et al. /16/, Zhuravlev et al./17/               
      Capture = 15.2 +- 1.2 b                                     
         Gavrilov and Goncharov/18/                               
      Resonance integral of capture = 626 +- 53 b                 
         Gavrilov and Goncharov/18/                               
                                                                  
  Unresolved resonance parameters (1 - 100 keV)                   
    Parameters (URP) were determined with ASREP code/19/ so as    
    to reproduce the cross sections in this energy range. URP are 
    used only for self-shielding calculations.                    
                                                                  
     Thermal cross sections and resonance integrals (at 300K)     
    -------------------------------------------------------       
                    0.0253 eV    reson. integ.(*)                 
                     (barns)       (barns)                        
    -------------------------------------------------------       
    total            28.65                                        
    elastic          12.39                                        
    fission           1.022           13.3                        
    capture          15.24           626                          
    -------------------------------------------------------       
         (*) In the energy range from 0.5 eV to 10 MeV.           
                                                                  
                                                                  
MF= 3 Neutron cross sections                                      
  Cross sections above the resolved resonance region except for   
  the elastic scattering (MT=2) and fission cross sections (MT=18,
  19, 20, 21, 38) were calculated with CCONE code/2/.             
                                                                  
  MT= 1 Total cross section                                       
    The cross section was calculated with CC OMP of Soukhovitskii 
    et al./20/                                                    
                                                                  
  MT= 2 Elastic scattering cross section                          
    Calculated as total - non-elastic scattering cross sections.  
                                                                  
  MT=18 Fission cross section                                     
    The following experimental data were analyzed in the energy   
    range above 1 keV with GMA code /21/:                         
                                                                  
       Authors        Energy range     Data points  Reference     
       Moore+         950eV - 2.83MeV       548      /13/         
       Fomushkin+     0.30 - 4.0MeV          17      /22/         
       Vorotnikov+    0.39 - 1.28MeV          8      /23/         
       Maguire Jr.+   0.94 - 79.5keV         49      /14/         
       Fomushkin+     14.1 MeV                1      /24/         
       Fursov+        0.169 - 6.842MeV       45      /25/(*1)     
                                                                  
        (*1) Relative to Pu-239 fission. These data were converted
             to cross sections using JENDL-3.3 data.              
                                                                  
    Between 7 and 20 MeV, data were determined by eye-guiding.    
                                                                  
    The results of GMA were used to determine the parameters in   
    the CCONE calculation.                                        
                                                                  
  MT=19, 20, 21, 38 Multi-chance fission cross sections           
    Calculated with CCONE code, and renormalized to the total     
    fission cross section (MT=18).                                
                                                                  
                                                                  
MF= 4 Angular distributions of secondary neutrons                 
  MT=2 Elastic scattering                                         
    Calculated with CCONE code.                                   
                                                                  
  MT=18 Fission                                                   
    Isotropic distributions in the laboratory system were assumed.
                                                                  
                                                                  
MF= 5 Energy distributions of secondary neutrons                  
  MT=18 Fission neutron spectra                                   
    Below 6 MeV, calculated by Ohsawa /26/ with modified          
    Madland-Nix formula considering multi-mode fission processes  
    (standard-1, standard-2, superlong).                          
    Above 7 MeV, calculated with CCONE code/2/.                   
                                                                  
                                                                  
MF= 6 Energy-angle distributions                                  
    Calculated with CCONE code.                                   
    Distributions from fission (MT=18) are not included.          
                                                                  
                                                                  
MF=12 Photon production multiplicities                            
  MT=18 Fission                                                   
    Calculated from the total energy released by the prompt       
    gamma-rays due to fission given in MF=1/MT=458 and the        
    average energy of gamma-rays.                                 
                                                                  
                                                                  
MF=14 Photon angular distributions                                
  MT=18 Fission                                                   
    Isotoropic distributions were assumed.                        
                                                                  
                                                                  
MF=15 Continuous photon energy spectra                            
  MT=18 Fission                                                   
    Experimental data measured by Verbinski et al./27/ for        
    Pu-239 thermal fission were adopted.                          
                                                                  
                                                                  
MF=31 Covariances of average number of neutrons per fission       
  MT=452 Number of neutrons per fission                           
    Combination of covariances for MT=455 and MT=456.             
                                                                  
  MT=455                                                          
    Error of 15% was assumed below 5 MeV and above 5 MeV,         
    respectively.                                                 
                                                                  
  MT=456                                                          
    Covariance was obtained by fitting a linear function to the   
    at 0.0 and 5.0 MeV with uncertainties of 8% and 7.5%,         
    respectively.                                                 
                                                                  
                                                                  
MF=32 Covariances of resonance parameters                         
    Format of LCOMP=0 was adopted.                                
                                                                  
    Standard deviations were adopted from Belanova et al./12/,    
    Moore and Keyworth/13/ and Maguire et al./14/                 
                                                                  
    For parameters having no information on uncertainties, the    
    following errors were assumed:                                
        0.1% to resonance energies                                
        10%  to other parameters                                  
                                                                  
MF=33 Covariances of neutron cross sections                       
  Covariances were given to all the cross sections by using       
  KALMAN code/28/ and the covariances of model parameters         
  used in the theoretical calculations.                           
                                                                  
  For the following cross sections, covariances were determined   
  by different methods.                                           
                                                                  
  MT=1, 2 Total and elastic scattering cross sections             
    In the resonance region (below 1 keV), uncertainty of 20%     
    was added.                                                    
                                                                  
  MT=18 Fission cross section                                     
    In the resonance region, the following errors were added:     
        1.0e-5 to 5eV   15%                                       
        5eV to 500eV    10%                                       
        500eV to 1keV   10%                                       
    Above the resonance region, cross section was evaluated with  
    GMA code/21/. Error of 5 % was added to the standard          
    deviations obatianed.                                         
                                                                  
  MT=102 Capture cross section                                    
    In the resonance region from 5 eV to 1 keV, addtional error   
    of 10 % was given.                                            
                                                                  
    Above 1 keV, covariance matrix was obtained with CCONE and    
    KALMAN codes/28/.                                             
                                                                  
                                                                  
MF=34 Covariances for Angular Distributions                       
  MT=2 Elastic scattering                                         
    Covariances were given only to P1 components.                 
                                                                  
                                                                  
MF=35 Covariances for Energy Distributions                        
  MT=18 Fission spectra                                           
    Below 6 MeV, covarinaces of Pu239 fission spectra given in    
    JENDL-3.3 were adopted after multiplying a factor of 9.       
    Above 6 MeV, estimated with CCONE and KALMAN codes.           
                                                                  
                                                                  
***************************************************************** 
  Calculation with CCONE code                                     
***************************************************************** 
                                                                  
  Models and parameters used in the CCONE/2/ calculation          
  1) Coupled channel optical model                                
     Levels in the rotational band were included. Optical model   
     potential and coupled levels are shown in Table 1.           
                                                                  
  2) Two-component exciton model/29/                              
    * Global parametrization of Koning-Duijvestijn/30/            
      was used.                                                   
    * Gamma emission channel/31/ was added to simulate direct     
      and semi-direct capture reaction.                           
                                                                  
  3) Hauser-Feshbach statistical model                            
    * Moldauer width fluctuation correction/32/ was included.     
    * Neutron, gamma and fission decay channel were included.     
    * Transmission coefficients of neutrons were taken from       
      coupled channel calculation in Table 1.                     
    * The level scheme of the target is shown in Table 2.         
    * Level density formula of constant temperature and Fermi-gas 
      model were used with shell energy correction and collective 
      enhancement factor. Parameters are shown in Table 3.        
    * Fission channel:                                            
      Double humped fission barriers were assumed.                
      Fission barrier penetrabilities were calculated with        
      Hill-Wheler formula/33/. Fission barrier parameters were    
      shown in Table 4. Transition state model was used and       
      continuum levels are assumed above the saddles. The level   
      density parameters for inner and outer saddles are shown in 
      Tables 5 and 6, respectively.                               
    * Gamma-ray strength function of Kopecky et al/34/,/35/       
      was used. The prameters are shown in Table 7.               
                                                                  
                                                                  
------------------------------------------------------------------
                              Tables                              
------------------------------------------------------------------
                                                                  
Table 1. Coupled channel calculation                              
  --------------------------------------------------              
  * rigid rotor model was applied                                 
  * coupled levels = 0,1,2,3,4 (see Table 2)                      
  * optical potential parameters /20/                             
    Volume:                                                       
      V_0       = 49.97    MeV                                    
      lambda_HF = 0.01004  1/MeV                                  
      C_viso    = 15.9     MeV                                    
      A_v       = 12.04    MeV                                    
      B_v       = 81.36    MeV                                    
      E_a       = 385      MeV                                    
      r_v       = 1.2568   fm                                     
      a_v       = 0.633    fm                                     
    Surface:                                                      
      W_0       = 17.2     MeV                                    
      B_s       = 11.19    MeV                                    
      C_s       = 0.01361  1/MeV                                  
      C_wiso    = 23.5     MeV                                    
      r_s       = 1.1803   fm                                     
      a_s       = 0.601    fm                                     
    Spin-orbit:                                                   
      V_so      = 5.75     MeV                                    
      lambda_so = 0.005    1/MeV                                  
      W_so      = -3.1     MeV                                    
      B_so      = 160      MeV                                    
      r_so      = 1.1214   fm                                     
      a_so      = 0.59     fm                                     
    Coulomb:                                                      
      C_coul    = 1.3                                             
      r_c       = 1.2452   fm                                     
      a_c       = 0.545    fm                                     
    Deformation:                                                  
      beta_2    = 0.213                                           
      beta_4    = 0.056                                           
      beta_6    = 0.0015                                          
                                                                  
  * Calculated strength function                                  
    S0= 1.01e-4 S1= 3.17e-4 R'=  9.16 fm (En=1 keV)               
  --------------------------------------------------              
                                                                  
Table 2. Level Scheme of Cm-244                                   
  -------------------                                             
  No.  Ex(MeV)   J PI                                             
  -------------------                                             
   0  0.00000   0  +  *                                           
   1  0.04297   2  +  *                                           
   2  0.14235   4  +  *                                           
   3  0.29621   6  +  *                                           
   4  0.50179   8  +  *                                           
   5  0.97000   3  -                                              
   6  0.98491   0  +                                              
   7  1.02076   2  +                                              
   8  1.03800   2  +                                              
   9  1.04019   6  +                                              
  10  1.08418   2  +                                              
  11  1.10591   2  -                                              
  -------------------                                             
  *) Coupled levels in CC calculation                             
                                                                  
Table 3. Level density parameters                                 
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Cm-245 18.8322  0.7667  1.4601  0.3623 -0.5771  2.6382         
   Cm-244 19.1414  1.5364  1.5347  0.3530  0.2436  3.3454         
   Cm-243 18.3259  0.7698  1.3577  0.3635 -0.5169  2.5698         
   Cm-242 18.6337  1.5428  1.3581  0.3517  0.3362  3.2428         
   Cm-241 18.5675  0.7730  1.0938  0.3935 -0.8080  2.9546         
  --------------------------------------------------------        
                                                                  
Table 4. Fission barrier parameters                               
  ----------------------------------------                        
  Nuclide     V_A    hw_A     V_B    hw_B                         
              MeV     MeV     MeV     MeV                         
  ----------------------------------------                        
   Cm-245   6.050   0.500   5.700   0.420                         
   Cm-244   6.100   0.900   5.100   0.600                         
   Cm-243   6.150   0.600   5.800   0.400                         
   Cm-242   6.200   1.040   4.900   0.600                         
   Cm-241   6.300   0.800   5.000   0.520                         
  ----------------------------------------                        
                                                                  
Table 5. Level density above inner saddle                         
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Cm-245 20.7155  0.8944  2.6000  0.3342 -1.6357  2.9944         
   Cm-244 20.6427  1.7925  2.6000  0.3275 -0.6303  3.7925         
   Cm-243 20.5699  0.8981  2.6000  0.3281 -1.5248  2.8981         
   Cm-242 20.4971  1.7999  2.6000  0.3288 -0.6230  3.7999         
   Cm-241 20.4242  0.9018  2.6000  0.3294 -1.5211  2.9018         
  --------------------------------------------------------        
                                                                  
Table 6. Level density above outer saddle                         
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Cm-245 20.7155  0.8944  0.7400  0.3596 -0.8163  2.8944         
   Cm-244 20.6427  1.7925  0.7000  0.3455  0.2502  3.5925         
   Cm-243 20.5699  0.8981  0.6600  0.3619 -0.8115  2.8981         
   Cm-242 20.4971  1.7999  0.6200  0.3631  0.0909  3.7999         
   Cm-241 20.4242  0.9018  0.5800  0.3643 -0.8066  2.9018         
  --------------------------------------------------------        
                                                                  
Table 7. Gamma-ray strength function for Cm-245                   
  --------------------------------------------------------        
  * E1: ER = 11.43 (MeV) EG = 2.73 (MeV) SIG = 326.80 (mb)        
        ER = 14.33 (MeV) EG = 4.20 (MeV) SIG = 424.50 (mb)        
  * M1: ER =  6.55 (MeV) EG = 4.00 (MeV) SIG =   1.45 (mb)        
  * E2: ER = 10.07 (MeV) EG = 3.17 (MeV) SIG =   7.06 (mb)        
  --------------------------------------------------------        
                                                                  
                                                                  
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