95-Am-241

 95-Am-241 JAEA+      EVAL-JAN10 O.Iwamoto,T.Nakagawa,T.Ohsawa,+  
                      DIST-JUL13                       20130626   
----JENDL-4.0u1       MATERIAL 9543                               
-----INCIDENT NEUTRON DATA                                        
------ENDF-6 FORMAT                                               
                                                                  
History                                                           
07-05 New theoretical calculation was made with CCONE code.       
07-09 Isomeric ratio was revised.                                 
07-11 Isomeric ratio was revised.                                 
08-03 Interpolation of (5,18) was changed.                        
      Data were compiled as JENDL/AC-2008/1/.                     
09-03 (MF2,MT151) was revised.                                    
09-08 (MF1,MT458) was evaluated.                                  
09-12 (1,455) and (2,151) were revised.                           
10-01 Data of prompt gamma rays due to fission were given.        
10-03 Covariance data were given.                                 
13-06 QI for an isomer in (MF9,MT102) was corrected.              
      (MF8,MT102) MATP was removed.                               
                                                                  
                                                                  
MF= 1                                                             
  MT=452 Total neutron per fission                                
    Sum of MT=455 and 456.                                        
                                                                  
  MT=455 Delayed neutrons                                         
    Determined from nu-d of the following three nuclides and      
    partial fission cross sections calculated with CCONE code/2/. 
                                                                  
      Am-242 = 0.0049   Saleh et al./3/                           
      Am-241 = 0.0016 *1)                                         
      Am-240 = 0.0011 *1)                                         
             *) A half of systematics by Tuttle/4/,               
                Benedetti et al./5/ and Waldo et al./6/           
                                                                  
    Decay constants were adopted from Saleh et al./3/ and Brady   
    and England/7/.                                               
                                                                  
  MT=456 Prompt neutrons per fission                              
    The data measured by Jaffey et al./8/, Khokhlov et al./9/     
    and Drapchinsky et al./10/ were fitted by a linear            
    function/11/.                                                 
                                                                  
  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/12/. 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 2000/13/ does 
    not include average neutron energy values, the average values 
    were calculated using the formula shown in the report by      
    T.R. England/14/. The fractions of prompt energy were         
    calculated using the fractions of Sher's evaluation/15/ 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, below 150 eV)              
    Resonance parameters adopted in JENDL-3.3 were revised mainly 
    in a low energy region. The positive resonances below 12 eV   
    were modified on the basis of new parameters reported by      
    Jandel el al./16/. The neutron widths were multiplied by      
    a factor of 1.029. The parameters below 1.27-eV resonance     
    were further adjusted to the fission cross section of Dabbs   
    et al./17/ Parameters of negative resonances were adjusted    
    so as to reproduce the following thermal cross sections:      
                                                                  
      Capture = 684 +- 15 b                                       
                Kalebin et al./18/, Shinohara et al./19/, Fioni et
                al./20/, Bringer et al./21/, Jandel et al./16/    
      Capture to ground state  = 620.1 +- 7.8 b                   
                Harbour et al./22/, Gavrilov et al./23/, Shinohara
                et al./19/, Maidana et al./24/, Fioni et al./20/, 
                Nakamura et al./25/                               
      Capture to meta stable st=  64.8 +- 3.6 b                   
                Shinohara et al./19/, Fioni et al./20/ and others 
      Fission = 3.12 +- 0.06 b                                    
                Zhuravlev et al./26/, Dabbs et al./17/, Yamamoto  
                et al./27/, and others.                           
                                                                  
    The present resolved resonance parameters give the total      
    cross section larger than experimental data measured by       
    Adamchuk et al./28/ and Kalebin et al./18/                    
                                                                  
  Unresolved resonance parameters                                 
    Parameters were determined with ASREP code/29/ so as to       
    reproduce the cross sections in the energy range from 150 eV  
    to 40 keV. They are used only for self-shielding calculations.
                                                                  
      Thermal cross sections and resonance integrals (300K)       
    -------------------------------------------------------       
                    0.0253 eV    reson. integ.(*)                 
    -------------------------------------------------------       
    total           699.22                                        
    elastic          11.82                                        
    fission           3.122           13.3                        
    capture         684.28          1590                          
    -------------------------------------------------------       
         (*) 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./30/ The parameters were adjusted using the experimental
    data of Phillips and Howe/31/.                                
                                                                  
  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 with the GMA    
    code /32/:                                                    
     Cance+/33/, Hage+/34/, Aleksandrov+/35/, Dabbs+/17/,         
     Vorotnikov+/36/, Yamamoto+/27/, Golovnya/37/, Baba+/38/.     
                                                                  
    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).                                
                                                                  
  MT=102 Capture cross section                                    
    Calculated with CCONE code. The experimental data of Wisshak  
    and Kaeppeler/39/, Vanpraet et al./40/, Gayther and Thomas/41/
    and Ivanova et al./42/ were used to determine the parameters  
    in the CCONE calculation.                                     
                                                                  
                                                                  
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 Prompt neutrons                                           
    Below 6 MeV, calculated with modified Madland-Nix formula     
    considering multi-mode fission processes (standard-1,         
    standard-2, superlong) by Ohsawa/43/.                         
    Above 7 MeV, calculated with CCONE code/2/.                   
                                                                  
  MT=455 Delayed neutrons                                         
    Calculated by Brady and England/7/. Fractions of 6            
    temporal groups were adopted from Saleh et al./3/.            
                                                                  
                                                                  
MF= 6 Energy-angle distributions                                  
    Calculated with CCONE code.                                   
    Distributions from fission (MT=18) are not included.          
                                                                  
                                                                  
MF= 8 Radioactive nuclide production                              
  MT=102 Capture cross section                                    
    (same as JENDL-3.3)                                           
    Decay data were taken from ENSDF.                             
                                                                  
                                                                  
MF= 9 Multiplicities for production of radioactive elements       
  MT=102 Capture cross section                                    
    Isomeric ratio (IR) was calculated with CCONE code above 100  
    eV.  IR to ground state (IR-g) was normalized to 0.84 at 300  
    keV/44/.                                                      
    IR-g below 0.1 eV was based on experimental data of Harbour   
    et al./22/, Gavlilov et al./23/, Wisshak et al./45/, Shinohara
    et al./19/, Fioni et al./20/, Bringer et al./46/. Average     
    IR-g = 0.896 +-0.002.                                         
    Above 0.1 eV, the data were connected straighly to 0.859 at   
    1 eV, and the CCONE calculations above 100 eV in the log-     
    linear scale.                                                 
                                                                  
                                                                  
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./47/ 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                                                          
    Standard deviation was roughly estimated as 5% below 5 MeV,   
    15% above 5 MeV.                                              
                                                                  
  MT=456                                                          
    Covariance was obtained by fitting to the experimental        
    data (see MF1,MT456).                                         
                                                                  
                                                                  
MF=32 Covariances of resonance parameters                         
    Format of LCOMP=0 was adopted.                                
                                                                  
    Standard diviations of resonance parameters were taken from   
    Ref./16/ below 12 eV, and from the JENDL-3.3 covariance       
    file /11/ above 12 eV. They were based on Derrien and         
    Lucas /48/ and Mughabghab /49/. For the levels whose          
    information are not given in those references, assumed were   
    standard deviations of 0.1 % for resonance energies, and 10   
    % for neutron, capture and fission widths.                    
                                                                  
                                                                  
MF=33 Covariances of neutron cross sections                       
  Covariances were given to all the cross sections by using       
  KALMAN code/50/ 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 resolved resonance region, uncertainty of 15% was      
    added to the contributions from resonance parameter           
    uncertainties.                                                
                                                                  
    Above 150 eV, estimated with CCONE and KALMAN codes.          
                                                                  
  MT=18 Fission cross section                                     
    In the resolved resonance region, uncertainty of 5% was added 
    to the contributions from resonance parameter uncertainties.  
                                                                  
    Above 150 eV, the fission cross section was evaluated with    
    GMA code/32/. The following errors were added to the GMA      
    results:                                                      
        150 - 5000 eV   10 %                                      
          5 - 50 keV     5 %                                      
         50 - 500 keV    3 %                                      
        0.5 - 5 MeV      1 %                                      
                                                                  
  MT=102 Capture cross section                                    
    In the resolved resonance region, uncertainty of 5% was added 
    to the contributions from resonance parameter uncertainties.  
                                                                  
    In the energy range below 150 eV, the following addtional     
    errors were added:                                            
      0.1    - 5   eV     10 %                                    
      5      - 150 eV     15 %                                    
                                                                  
    Above 150 eV, covariance matrix was obtained with CCONE and   
    KALMAN codes/50/.                                             
                                                                  
                                                                  
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/51/                              
    * Global parametrization of Koning-Duijvestijn/52/            
      was used.                                                   
    * Gamma emission channel/53/ was added to simulate direct     
      and semi-direct capture reaction.                           
                                                                  
  3) Hauser-Feshbach statistical model                            
    * Moldauer width fluctuation correction/54/ 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/55/. 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/56/,/57/       
      was used. The prameters are shown in Table 7.               
                                                                  
                                                                  
------------------------------------------------------------------
                              Tables                              
------------------------------------------------------------------
                                                                  
Table 1. Coupled channel calculation                              
  --------------------------------------------------              
  * rigid rotor model was applied                                 
  * coupled levels = 0,1,2,3,5,11 (see Table 2)                   
  * optical potential parameters /30/                             
    Volume:                                                       
      V_0       = 48       MeV                                    
      lambda_HF = 0.004    1/MeV                                  
      C_viso    = 15.9     MeV                                    
      A_v       = 12.04    MeV                                    
      B_v       = 81.36    MeV                                    
      E_a       = 385      MeV                                    
      r_v       = 1.255    fm                                     
      a_v       = 0.58     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       = 1.15     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    = 0.08                                            
      beta_6    = 0.0015                                          
                                                                  
  * Calculated strength function                                  
    S0= 0.99e-4 S1= 2.66e-4 R'=  9.49 fm (En=1 keV)               
  --------------------------------------------------              
                                                                  
Table 2. Level Scheme of Am-241                                   
  -------------------                                             
  No.  Ex(MeV)   J PI                                             
  -------------------                                             
   0  0.00000  5/2 -  *                                           
   1  0.04118  7/2 -  *                                           
   2  0.09370  9/2 -  *                                           
   3  0.15750 11/2 -  *                                           
   4  0.20588  5/2 +                                              
   5  0.23368 13/2 -  *                                           
   6  0.23520  7/2 +                                              
   7  0.23900  7/2 +                                              
   8  0.27300 13/2 -                                              
   9  0.27320  9/2 +                                              
  10  0.31980 11/2 +                                              
  11  0.31982 15/2 -  *                                           
  12  0.38110 13/2 +                                              
  13  0.41818 17/2 -                                              
  14  0.45310 15/2 +                                              
  15  0.45900 11/2 -                                              
  16  0.47181  3/2 -                                              
  17  0.49500 21/2 +                                              
  18  0.50445  5/2 -                                              
  19  0.52567 19/2 -                                              
  20  0.53090 17/2 +                                              
  -------------------                                             
  *) Coupled levels in CC calculation                             
                                                                  
Table 3. Level density parameters                                 
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Am-242 18.6337  0.0000  1.6845  0.2832 -0.6794  0.9948         
   Am-241 18.1961  0.7730  1.7328  0.3819 -0.7226  2.8365         
   Am-240 17.7611  0.0000  1.3474  0.2960 -0.6883  1.0000         
   Am-239 18.4349  0.7762  1.5592  0.3648 -0.5528  2.6354         
   Am-238 18.3685  0.0000  1.3698  0.2894 -0.6819  1.0000         
  --------------------------------------------------------        
                                                                  
Table 4. Fission barrier parameters                               
  ----------------------------------------                        
  Nuclide     V_A    hw_A     V_B    hw_B                         
              MeV     MeV     MeV     MeV                         
  ----------------------------------------                        
   Am-242   6.510   0.600   6.050   0.550                         
   Am-241   6.100   0.800   5.500   0.520                         
   Am-240   6.000   0.650   5.600   0.450                         
   Am-239   6.000   0.800   5.400   0.520                         
   Am-238   5.700   0.650   2.100   0.450                         
  ----------------------------------------                        
                                                                  
Table 5. Level density above inner saddle                         
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Am-242 20.8697  0.0000  2.6000  0.3254 -2.4113  2.0000         
   Am-241 21.3526  0.9018  2.6000  0.3213 -1.4929  2.9018         
   Am-240 21.2764  0.0000  2.6000  0.3219 -2.3947  2.0000         
   Am-239 21.2001  0.9056  2.6000  0.3225 -1.4891  2.9056         
   Am-238 21.1238  0.0000  2.6000  0.3231 -2.3946  2.0000         
  --------------------------------------------------------        
                                                                  
Table 6. Level density above outer saddle                         
  --------------------------------------------------------        
  Nuclide      a*    Pair  Eshell       T      E0  Ematch         
            1/MeV     MeV     MeV     MeV     MeV     MeV         
  --------------------------------------------------------        
   Am-242 21.4288  0.0000  0.5600  0.3688 -1.8681  2.2000         
   Am-241 21.3526  0.9018  0.5200  0.3405 -0.6297  2.7018         
   Am-240 21.2764  0.0000  0.4800  0.3416 -1.5310  1.8000         
   Am-239 21.2001  0.9056  0.4400  0.3428 -0.6250  2.7056         
   Am-238 21.1238  0.0000  0.4000  0.3440 -1.5301  1.8000         
  --------------------------------------------------------        
                                                                  
Table 7. Gamma-ray strength function for Am-242                   
  --------------------------------------------------------        
  * E1: ER = 11.53 (MeV) EG = 2.77 (MeV) SIG = 243.63 (mb)        
        ER = 14.32 (MeV) EG = 4.20 (MeV) SIG = 487.26 (mb)        
  * M1: ER =  6.58 (MeV) EG = 4.00 (MeV) SIG =   1.27 (mb)        
  * E2: ER = 10.11 (MeV) EG = 3.21 (MeV) SIG =   6.93 (mb)        
  --------------------------------------------------------        
                                                                  
                                                                  
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