56-Ba-137 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G. DIST-MAY10 20091217 ----JENDL-4.0 MATERIAL 5646 -----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 were modified. *********************************************************** 10-03 JENDL-4.0 was made. Resoloved resonance parameters were evaluated by K.Shibata. Unresolved resonance parameters were evaluated by S.Kunieda. The LSSF=1 was applied. Compiled by S.Kunieda ***** modified parts for JENDL-4.0 ******************** (1,451) Updated. (2,151) Updated. (3,1) Re-calculated from partial cross sections. (3,2) Calculated from URP in lower energy range. (3,4) Re-calculated from partial cross sections. (3,102) Calculated from URP in lower energy range. *********************************************************** mf = 1 General information mt=451 Comments and dictionary mf = 2 Resonance parameters mt=151 Resolved and unresolved resonance parameters Resolved resonance region (MLBW formula) : below 11.885 keV For JENDL-2, evaluation was made by Kikuchi/3/. Below 1.7 keV, parameters were determined from the experimental data of Alves et al./4/ and Van de Vyver and Pattenden/5/. Average radiation widths were assumed to be 0.08 eV for s-wave resonances and 0.068 eV for p-wave ones except for 420- and 578-eV levels. Above 3 keV, evaluation was based on the data of Musgrove et al./6/. Many artificial levels were generated with stat/7/ by assuming d=380 eV, S0=0.57e-4, S1=0.45e-4. A negative resonance was added at -26 eV so as to reproduce the capture cross section of 5.1 +- 0.4 barns at 0.0253 eV/8/. For JENDL-3, the resonance parameters of JENDL-2 were updated by using the newest experimental data by Mizumoto /9/. The resonance energies and neutron widths were replaced by Mizumoto's data in the energy range from 418.3 eV to 14.941 keV. Average radiation width and scattering radius were taken from Mughabghab et al./8/ total spin J of some resonances was tentatively estimated with a random number method. ************************************************************* In JENDL-4, the parameters for the negative resonance was re-adjusted so as to reproduce the thermal capture cross section recommended by Mughabghab./26/ ************************************************************* Unresolved resonance region : 11.885 keV - 100 keV Initial values of neutron strength functions, S0 and S1, were adopted from the recommendation by Mughabghab et al., and S2 was taken from calculation with CASTHY/10/. The parameters were adjusted to reproduce the capture cross section measured by Musgrove et al./11/ The effective scattering radius was obtained from fitting to the calculated total cross section at 100 keV. The radiation width Gg was adopted from Ref./8/. Typical values of the parameters at 70 keV: S0 = 0.695e-4, S1 = 0.525e-4, S2 = 0.949e-4, Sg = 3.91e-4, Gg = 0.080 eV, R = 5.729 fm. *************************************************************** For JENDL-4.0, the unresolved resonance parameters were re-evaluated by the ASREP /27/ code so as to reproduce the total and capture cross sections given in JENDL3.3 in the energy region from 11.885 keV to 100 keV. The parameters should be used only for self-shielding calculations. *************************************************************** Thermal cross sections & resonance integrals at 300 K ---------------------------------------------------------- 0.0253 eV res. integ. (*) (barns) (barns) ---------------------------------------------------------- Total 7.49733E+00 Elastic 3.89613E+00 n,gamma 3.60120E+00 4.25658E+00 ---------------------------------------------------------- (*) 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, by taking account of competing reactions, of which cross sections were calculated with PEGASUS/12/ 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 total cross section by changing Ws and rso of Iijima-Kawai potential/13/. The OMP's for charged particles are as follows: proton = Perey/14/ alpha = Huizenga and Igo/15/ deuteron = Lohr and Haeberli/16/ helium-3 and triton = Becchetti and Greenlees/17/ Parameters for the composite level density formula of Gilbert and Cameron/18/ were evaluated by Iijima et al./19/ 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 /20/. 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./21/. no. energy(MeV) spin-parity gr. 0.0 3/2 + 1 0.2792 1/2 + 2 0.6616 11/2 - 3 1.2900 5/2 + 4 1.4629 5/2 + 5 1.7900 7/2 - 6 1.8400 1/2 + 7 1.9000 5/2 + 8 2.0400 5/2 + Levels above 2.12 MeV were assumed to be overlapping. 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 (3.65e-04) was adjusted to reproduce the capture cross section of 33 milli-barns at 100 keV measured by Musgrove et al./11/ 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 = 32 (n,n'd) 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 (= 435.5) was estimated by the formula derived from Kikuchi-Kawai's formalism/23/ 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) 1710.00 mb (systematics of Wen Den Lu+/24/) (n,p) 3.32 mb (systematics of Forrest/25/) (n,alpha) 1.59 mb (systematics of Forrest) 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. For other reactions, isotropic distri- butions 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 from 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-133 1.600E+01 6.250E-01 2.327E+00 5.284E+00 1.120E+00 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 55-CS-134 1.598E+01 6.450E-01 1.710E+01 4.505E+00 0.0 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 56-BA-135 1.902E+01 5.820E-01 2.277E+00 6.108E+00 1.580E+00 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 --------------------------------------------------------------- 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 5.625 for Ba-137 and 7.914 for Ba-138. 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) Alves, R.N., et al.: Nucl. Phys., A134, 118 (1969). 5) Van de Vyver, R.E., Pattenden, N.J.: Nucl. Phys., A177, 393 (1971). 6) Musgrove, A.R. de L., et al.: Aust. J. Phys., 29, 157 (1976). 7) Kikuchi, Y.: JAERI-M 6248 (1975). 8) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. I, Part A", Academic Press (1981). 9) Mizumoto, M.: J. Nucl. Sci. Technol., 25, 757 (1988). 10) Igarasi, S. and Fukahori, T.: JAERI 1321 (1991). 11) Musgrove, A.R. de L., et al.: Proc. Int. Conf. on Neutron Physics and Nucl. Data for Reactors, Harwell 1978, 449. 12) Iijima, S. et al.: JAERI-M 87-025, p. 337 (1987). 13) Iijima, S. and Kawai, M.: J. Nucl. Sci. 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