96-Cm-247 JAEA+ EVAL-FEB10 O.Iwamoto, T.Nakagawa, et al. DIST-MAY10 20100318 ----JENDL-4.0 MATERIAL 9646 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT History 05-06 Fission cross section was evaluated with GMA. 06-05 Resonance parameters were modified. 06-12 GMA results were revised. 07-05 New calculation was made with CCONE code. 08-03 Recalculation with CCONE code was performed. Data were compiled as JENDL/AC-2008/1/. 10-02 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 (same as JENDL-3.3) Semi-empirical formula by Tuttle/2/. MT=456 Number of prompt neutrons per fission (same as JENDL-3.3) At the 0 eV, the experimental data of Zhuravlev et al./3/ was adopted. An energy-dependent term was based on the semi- empirical formula by Howerton/4/. MF= 2 Resonance parameters MT=151 Resolved resonance parameters (MLBW: 1.0E-5 - 60 eV) Resonance parameters of Moore and Keyworth/5/ and Danon et al./6/ were adopted. Resonance energies of Ref./5/ were shifted down by 0.3%. The parameters were adjusted to the measured fission cross sections/5,6/. The thermal cross sections to be reproduced: Fission = 94.6 +- 3.1 b Danon et al./6/, Diamond et al./7/, Benjamin et al./8/, Zhuravlev et al./9/, etc. Capture = 60 +- 10 b Gavrilov et al./10/ Unresolved resonance parameters (60 eV - 40 keV) Parameters were determined with ASREP code/11/ so as to reproduce the cross sections. They are used only for self- shielding calculations. Thermal cross sections and resonance integrals (at 300K) ------------------------------------------------------- 0.0253 eV reson. integ.(*) (barns) (barns) ------------------------------------------------------- total 163.023 elastic 8.348 fission 94.744 945 capture 59.931 503 ------------------------------------------------------- (*) 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/12/. MT= 1 Total cross section The cross section was calculated with CC OMP of Soukhovitskii et al./13/ MT= 2 Elastic scattering cross section Calculated as total - non-elastic scattering cross sections. MT=18 Fission cross section (Above 115 eV) The following experimental data were analyzed in the energy range from 115 eV to 20 MeV with the GMA code /14/: Authors Energy range Data points Reference Moore+ 50eV - 1.9MeV 3523 /5/ Fomushkin+ 20keV - 3MeV 27 /15/ Fomushkin+ 14 MeV 1 /16/ Danon+ 500eV - 98keV 45 /17/ Danon+ 0.01eV - 9.8keV 1018 /6/ Ivanin+ 130keV - 8.3MeV 81 /18/ Fursov+ 135keV - 15MeV 68 /19/(*1) (*1) Ratio to Pu-239 fission. JENDL-3.3 data were used to convert them to cross sections. The results of GMA were used to determine the parameters in the CCONE calculation. In the energy regions from 40 to 500keV and above 6 MeV, eye-guided curves were adopted. 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 Prompt neutron spectra Calculated with CCONE code/12/. 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 which was estimated from its systematics, 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./20/ for Pu-239 thermal fission were adopted. MF=31 Covariances of average number of neutrons per fission MT=452 Number of neutrons per fission Sum of covariances for MT=455 and MT=456. MT=455 Error of 15% was assumed. MT=456 Covariance was obtained by fitting a linear function to the data at 0.0 and 5.0 MeV with an uncertainty of 4% and 5%, respevtively. The uncertainty at 0 eV was estimated from the experimental data of Zhuravlev et al./3/ MF=32 Covariances of resonance parameters MT=151 Resolved resonance parameterss Format of LCOMP=0 was adopted. Uncertainties of parameters were taken from Mughabghab /21/. For the parameters without any information on uncertainty, the following uncertainties were assumed: Resonance energy 0.1 % Neutron width 10 % Capture width 30 % Fission width 20 % They were further modified by considering experimental data of the fission cross section at the thermal neutron energy. MF=33 Covariances of neutron cross sections Covariances were given to all the cross sections by using KALMAN code/22/ and the covariances of model parameters used in the cross-section calculations. For the fission cross section, covariances obtained with the GMA analysis were adopted. Standard deviations of about 10% were assumed in the energy region above 8 MeV. In the resolved resonance region, the following standard deviations were added to the contributions from resonance parameters: Total 10 % Elastic scattering 20 % Capture 20 % 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 Estimated with CCONE and KALMAN codes. ***************************************************************** Calculation with CCONE code ***************************************************************** Models and parameters used in the CCONE/12/ 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/23/ * Global parametrization of Koning-Duijvestijn/24/ was used. * Gamma emission channel/25/ was added to simulate direct and semi-direct capture reaction. 3) Hauser-Feshbach statistical model * Moldauer width fluctuation correction/26/ 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/27/. 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/28/,/29/ was used. The prameters are shown in Table 7. ------------------------------------------------------------------ Tables ------------------------------------------------------------------ Table 1. Coupled channel calculation -------------------------------------------------- * rigid rotor model was applied * coupled levels = 0,1,2,3,33 (see Table 2) * optical potential parameters /13/ 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 = 0.066 beta_6 = 0.0015 * Calculated strength function S0= 1.18e-4 S1= 2.99e-4 R'= 9.09 fm (En=1 keV) -------------------------------------------------- Table 2. Level Scheme of Cm-247 ------------------- No. Ex(MeV) J PI ------------------- 0 0.00000 9/2 - * 1 0.06167 11/2 - * 2 0.13465 13/2 - * 3 0.21900 15/2 - * 4 0.22738 5/2 + 5 0.26586 7/2 + 6 0.28541 7/2 + 7 0.30900 9/2 - 8 0.31830 9/2 + 9 0.33600 7/2 + 10 0.34590 9/2 + 11 0.37000 13/2 - 12 0.38100 11/2 + 13 0.39800 11/2 + 14 0.40490 1/2 + 15 0.41700 9/2 + 16 0.43300 3/2 + 17 0.43900 13/2 + 18 0.44800 5/2 + 19 0.50600 1/2 + 20 0.51670 7/2 + 21 0.51858 3/2 + 22 0.55000 9/2 + 23 0.58170 5/2 + 24 0.59200 9/2 + 25 0.60400 7/2 + ------------------- *) 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-248 18.5357 1.5240 2.0504 0.3482 0.2818 3.2555 Cm-247 18.3955 0.7635 1.7794 0.3734 -0.6804 2.7533 Cm-246 18.8984 1.5302 1.7310 0.3608 0.1621 3.4286 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 -------------------------------------------------------- Table 4. Fission barrier parameters ---------------------------------------- Nuclide V_A hw_A V_B hw_B MeV MeV MeV MeV ---------------------------------------- Cm-248 6.100 1.040 4.950 0.600 Cm-247 5.400 0.800 5.650 0.650 Cm-246 6.300 1.040 5.100 0.600 Cm-245 6.050 0.500 5.700 0.420 Cm-244 6.100 0.900 5.100 0.600 ---------------------------------------- Table 5. Level density above inner saddle -------------------------------------------------------- Nuclide a* Pair Eshell T E0 Ematch 1/MeV MeV MeV MeV MeV MeV -------------------------------------------------------- Cm-248 20.9336 1.5000 2.6000 0.3323 -1.0300 3.6000 Cm-247 20.8609 0.8908 2.6000 0.3256 -1.5320 2.8908 Cm-246 20.7882 1.6500 2.6000 0.3263 -0.7728 3.6500 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 -------------------------------------------------------- Table 6. Level density above outer saddle -------------------------------------------------------- Nuclide a* Pair Eshell T E0 Ematch 1/MeV MeV MeV MeV MeV MeV -------------------------------------------------------- Cm-248 20.9336 1.7780 0.8600 0.3706 -0.1043 3.9780 Cm-247 20.8609 0.8908 0.8200 0.3573 -0.8210 2.8908 Cm-246 20.7882 1.7852 0.7800 0.3658 -0.0107 3.8852 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 -------------------------------------------------------- Table 7. Gamma-ray strength function for Cm-248 -------------------------------------------------------- * E1: ER = 11.40 (MeV) EG = 2.71 (MeV) SIG = 331.48 (mb) ER = 14.30 (MeV) EG = 4.18 (MeV) SIG = 429.81 (mb) * M1: ER = 6.53 (MeV) EG = 4.00 (MeV) SIG = 1.48 (mb) * E2: ER = 10.03 (MeV) EG = 3.13 (MeV) SIG = 7.06 (mb) -------------------------------------------------------- References 1) O.Iwamoto et al.: J. Nucl. Sci. 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