95-Am-241 JAEA+ EVAL-JAN10 O.Iwamoto,T.Nakagawa,T.Ohsawa,+ DIST-DEC21 20180823 ----JENDL-5 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. 18-08 Resolved resonance parameters were revised by N.Iwamoto. 21-04 JENDL-5b1 (MF3,MT2) recalculated (MF3/MT18) modified from 0.8 to 4 MeV (MF3/MT19-21,38) deleted 21-10 JENDL-5b3 revised by N.Iwamoto (MF2/MT151) 5.8-eV resonance deleted. RRP and URRP revised. (MF3,6/MT102) revised. (MF8/MT4,16,17,18) added. (MF3/MT1,2,4) recalculated 21-10 JENDL-5b3 revised by N.Iwamoto (MF3/MT102) replaced into JENDL-4.0 and scaled (MF2/MT151) URP: derived with ASREP (MF3,MT1,2) recalculated 21-11 above 20 MeV, JENDL-4.0/HE merged by O.Iwamoto 21-11 (MF6/MT5) recoil spectrum added by O.Iwamoto 21-12 (MF32/MT151) modified by O.Iwamoto ER<19eV, REFIT results ER>19eV, Mendoza et al.,PRC97,054616(2018) 21-12 (MF33/MT1,2,18,102) modified by O.Iwamoto 0.1eV < En < 702eV, 10% unc. assumed 21-12 (MF1/MT452,456) by O.Iwamoto revise nu-p (En > 20 MeV) by a systematics (MF6/MT5) by O.Iwamoto modify multiplicity of ZAP=1 to compensate the revision of nu-p 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/1/. Am-242 = 0.0049 Saleh et al./2/ Am-241 = 0.0016 *1) Am-240 = 0.0011 *1) *) A half of systematics by Tuttle/3/, Benedetti et al./4/ and Waldo et al./5/ Decay constants were adopted from Saleh et al./2/ and Brady and England/6/. MT=456 Prompt neutrons per fission The data measured by Jaffey et al./7/, Khokhlov et al./8/ and Drapchinsky et al./9/ were fitted by a linear function/10/. 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/11/. 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 2000/12/ does not include average neutron energy values, the average values were calculated using the formula shown in the report by T.R. England/13/. The fractions of prompt energy were calculated using the fractions of Sher's evaluation/14/ 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./15/. 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./16/ Parameters of negative resonances were adjusted so as to reproduce the following thermal cross sections: Capture = 684 +- 15 b Kalebin et al./17/, Shinohara et al./18/, Fioni et al./19/, Bringer et al./20/, Jandel et al./15/ Capture to ground state = 620.1 +- 7.8 b Harbour et al./21/, Gavrilov et al./22/, Shinohara et al./18/, Maidana et al./23/, Fioni et al./19/, Nakamura et al./24/ Capture to meta stable st= 64.8 +- 3.6 b Shinohara et al./18/, Fioni et al./19/ and others Fission = 3.12 +- 0.06 b Zhuravlev et al./25/, Dabbs et al./16/, Yamamoto et al./26/, and others. The present resolved resonance parameters give the total cross section larger than experimental data measured by Adamchuk et al./27/ and Kalebin et al./17/ In JENDL-5 resonance capture and transmission data measured with ANNRI in J-PARC MLF/28/ were evaluated by REFIT in energies up to 19 eV. The fission widths were revised with the same Kernel values for fission cross section as those of JENDL-4.0. The 5.8-eV resonance is deleted because it is considered to be that of Np-237. The resonance parameters above 19 eV were taken from Mendoza et al./29/. Unresolved resonance parameters Parameters were determined with ASREP code/30/ 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 7.16880E+02 Elastic 4.65739E+00 Fission 3.20781E+00 8.35975E+00 n,gamma 7.09015E+02 1.82496E+03 ------------------------------------------------------- (*) 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/1/. MT= 1 Total cross section The cross section was calculated with CC OMP of Soukhovitskii et al./31/ The parameters were adjusted using the experimental data of Phillips and Howe/32/. 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 /33/: Cance+/34/, Hage+/35/, Aleksandrov+/36/, Dabbs+/16/, Vorotnikov+/37/, Yamamoto+/26/, Golovnya/38/, Baba+/39/. 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/40/, Vanpraet et al./41/, Gayther and Thomas/42/ and Ivanova et al./43/ 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/44/. Above 7 MeV, calculated with CCONE code/1/. MT=455 Delayed neutrons Calculated by Brady and England/7/. Fractions of 6 temporal groups were adopted from Saleh et al./2/. 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/45/. IR-g below 0.1 eV was based on experimental data of Harbour et al./21/, Gavlilov et al./22/, Wisshak et al./46/, Shinohara et al./18/, Fioni et al./19/, Bringer et al./47/. 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./48/ 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 /49/ and Mughabghab /50/. 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/51/ 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/33/. 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/51/. 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/1/ 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/52/ * Global parametrization of Koning-Duijvestijn/53/ was used. * Gamma emission channel/54/ was added to simulate direct and semi-direct capture reaction. 3) Hauser-Feshbach statistical model * Moldauer width fluctuation correction/55/ 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/56/. 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/57/,/58/ 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 /31/ 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) -------------------------------------------------------- References #1) O.Iwamoto et al.: J. Nucl. Sci. Technol., 46, 510 (2009). 1) O.Iwamoto: J. Nucl. Sci. 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