56-Ba-138 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G. DIST-MAY10 20091217 ----JENDL-4.0 MATERIAL 5649 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT =========================================================== Resonance parameters in JENDL-3.3 were revised for JENDL-4. =========================================================== =========================================================== JENDL-3.2 data were automatically transformed to JENDL-3.3. Interpolation of spectra: 22 (unit base interpolation) (3,251) deleted, T-matrix of (4,2) deleted, and others. =========================================================== History 84-10 Evaluation for JENDL-2 was made by JNDC FPND W.G./1/ 90-03 Modification for JENDL-3 was made/2/. 93-10 JENDL-3.2 was made by JNDC FPND W.G. ***** modified parts for JENDL-3.2 ******************** (2,151) Resolved resonance parameters (3,102) Re-normalization (3,2), (3,4), (3,51-91) and angular distributions Small effects of the re-normalization of capture cross section. ( < 0.3% ) *********************************************************** 10-03 JENDL-4.0 was made. Resoloved resonance parameters were evaluated by K.Shibata. Compiled by S.Kunieda ***** modified parts for JENDL-4.0 ******************** (1,451) Updated. (2,151) Updated. (3,1) Re-calculated from partial cross sections. (3,4) Re-calculated from partial cross sections. *********************************************************** mf = 1 General information mt=451 Comments and dictionary mf = 2 Resonance parameters mt=151 Resolved and unresolved resonance parameters Resolved resonance parameters for MLBW formula (below 100 keV) For JENDL-2, evaluation was made by Kikuchi /3/ mainly on the basis of the data measured by Musgrove et al./4/ up to 92 keV. Above 100 keV, neutron widths were adopted from Bilpuch et al./5/ Average capture widths were assumed to be 0.055+- 0.020 eV for s-wave resonances and 0.045+-0.020 eV for p-wave ones, and to be 0.095 eV in the energy range above 100 keV. A negative resonance was added at -6.22 keV so as to reproduce the capture cross section of 0.360+-0.036 barns at 0.0253 eV/6/. For JENDL-3, 10 resonances were newly asigned by taking the experimental data by Mizumoto/7/ in the energy range from 648 eV to 63.12 keV. Total spin J of some resonances was tenta- tively estimated with a random number method ************************************************************* In JENDL-4, the data above 100 keV were replaced with the ones obtained by Brusegan et al./28/ The radiation widths of 95 meV and 47 meV were assumed for s- and p-wave resonances, respectively. The parameters for the negative resonance were re-adjusted so as to reproduce the thermal capture cross section recommended by Mughabghab./29/ ************************************************************* No unresolved resonance region Thermal cross sections & resonance integrals at 300 K ---------------------------------------------------------- 0.0253 eV res. integ. (*) (barns) (barns) ---------------------------------------------------------- Total 6.44545E+00 Elastic 6.04108E+00 n,gamma 4.04376E-01 2.83528E-01 ---------------------------------------------------------- (*) Integrated from 0.5 eV to 10 MeV. 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/8/, by taking account of competing reactions, of which cross sections were calculated with PEGASUS/9/ standing on a preequilibrium and multi-step evaporation model. The OMP's for neutron given in Table 1 were determined to reproduce a systematic trend of the Ba-nat. Total cross section by changing Ws and rso of Iijima-Kawai potential /10/. The OMP's for charged particles are as follows: proton = Perey/11/ alpha = Huizenga and Igo/12/ deuteron = Lohr and Haeberli/13/ helium-3 and triton = Becchetti and Greenlees/14/ Parameters for the composite level density formula of Gilbert and Cameron/15/ were evaluated by Iijima et al./16/ 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 /17/. mt = 1 Total Spherical optical model calculation was adopted. mt = 2 Elastic scattering Calculated as (total - sum of partial cross sections). mt = 4, 51 - 91 Inelastic scattering Spherical optical and statistical model calculation was adopted. The level scheme was taken from Ref./18/. no. energy(MeV) spin-parity dwba cal. gr. 0.0 0 + 1 1.4359 2 + * 2 1.8987 4 + 3 2.0907 6 + 4 2.1896 2 + 5 2.2032 6 + 6 2.2180 2 + 7 2.3077 4 + 8 2.4156 5 + 9 2.4457 3 + 10 2.5832 1 + 11 2.5840 4 + 12 2.6396 2 + 13 2.7795 4 + 14 2.8517 3 + 15 2.8810 3 - * 16 2.9315 1 + 17 2.9912 3 + 18 3.0500 2 + 19 3.1560 4 + Levels above 3.164 MeV were assumed to be overlapping. For the levels with an asterisk, the contribution of direct inelastic scattering cross sections was calculated by the DWUCK-4 code/19/. Deformation parameters (beta2 = 0.0925 and beta3 = 0.118) were based on the data compiled by Raman et al./20/ and Spear/21/, respectively. mt = 102 Capture Spherical optical and statistical model calculation with CASTHY was adopted. Direct and semi-direct capture cross sections were estimated according to the procedure of Benzi and Reffo/22/ and normalized to 1 milli-barn at 14 MeV. The gamma-ray strength function (2.54e-06) was adjusted to the capture cross section of 2.7 milli-barns at 700 keV so as to reproduce the cross section measured by Johnsrud et al./23/ and Stavisskij and Tolstikov/24/ 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 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 (= 144.6) was estimated by the formula derived from Kikuchi-Kawai's formalism/25/ and level density parameters. Finally, the (n,2n), (n,p) and (n,alpha) cross sections were normalized to the following values at 14.5 MeV: (n,2n) 1750.00 mb (systematics of Wen Den Lu+/26/) (n,p) 2.80 mb (measured by Ikeda+/27/) (n,alpha) 2.10 mb (measured by Ikeda+) mt = 251 mu-bar Calculated with CASTHY. mf = 4 Angular distributions of secondary neutrons Legendre polynomial coefficients for angular distributions are given in the center-of-mass system for mt=2 and discrete inelas- tic levels, and in the laboratory system for mt=91. They were calculated with CASTHY. Contribution of direct inelastic scattering was calculated with DWUCK-4. For other reactions, isotropic distributions in the laboratory system were assumed. mf = 5 Energy distributions of secondary neutrons Energy distributions of secondary neutrons were calculated with PEGASUS for inelastic scattering to overlapping levels and for other neutron emitting reactions. TABLE 1 NEUTRON OPTICAL POTENTIAL PARAMETERS DEPTH (MEV) RADIUS(FM) DIFFUSENESS(FM) ---------------------- ------------ --------------- V = 41.8 R0 = 6.89 A0 = 0.62 WS = 2.95+0.789E RS = 7.098 AS = 0.35 VSO= 7.0 RSO= 6.89 ASO= 0.62 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 --------------------------------------------------------------- 54-XE-134 1.400E+01 6.300E-01 3.184E-01 5.224E+00 1.820E+00 54-XE-135 1.550E+01 5.565E-01 7.506E-01 4.010E+00 1.120E+00 54-XE-136 1.400E+01 6.500E-01 3.270E-01 5.679E+00 1.970E+00 54-XE-137 1.550E+01 5.565E-01 7.470E-01 4.010E+00 1.120E+00 55-CS-135 1.343E+01 6.537E-01 1.831E+00 4.203E+00 7.000E-01 55-CS-136 1.400E+01 6.000E-01 4.424E+00 2.967E+00 0.0 55-CS-137 1.336E+01 6.200E-01 9.986E-01 3.836E+00 8.500E-01 55-CS-138 1.470E+01 5.737E-01 4.715E+00 2.858E+00 0.0 56-BA-136 1.610E+01 6.500E-01 5.721E-01 6.928E+00 2.280E+00 56-BA-137 1.645E+01 5.640E-01 5.394E-01 4.905E+00 1.580E+00 56-BA-138 1.390E+01 7.200E-01 4.123E-01 7.233E+00 2.430E+00 56-BA-139 2.022E+01 4.800E-01 5.326E-01 4.629E+00 1.580E+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 7.914 for Ba-138 and 5.0 for Ba-139. 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) Kikuchi, Y. et al.: JAERI-M 86-030 (1986). 4) Musgrove, A.R. de L., et al.: Aust. J. Phys., 32, 213 (1979). 5) Bilpuch, E.G., et al.: Ann. Phys., 14, 387 (1961). 6) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. I, Part A", Academic Press (1981). 7) Mizumoto, M.: J. Nucl. Sci. Eng., 25, 757 (1988). 8) Igarasi, S. and Fukahori, T.: JAERI 1321 (1991). 9) Iijima, S. et al.: JAERI-M 87-025, p. 337 (1987). 10) Iijima, S. and Kawai, M.: J. Nucl. Sci. Technol., 20, 77 (1983). 11) Perey, F.G: Phys. Rev. 131, 745 (1963). 12) Huizenga, J.R. and Igo, G.: Nucl. Phys. 29, 462 (1962). 13) Lohr, J.M. and Haeberli, W.: Nucl. Phys. 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