56-Ba-140 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G. DIST-MAY10 20091217 ----JENDL-4.0 MATERIAL 5655 -----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 90-03 New evaluation for JENDL-3 was completed by JNDC FPND W.G./1/ 10-03 JENDL-4.0 was made. 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 No resolved resonance parameters Unresolved resonance region : 14 keV - 100 keV The neutron strength functions, S0, S1 and S2 were calculated with optical model code CASTHY/2/. The observed level spacing was determined to reproduce the capture cross section calculated with CASTHY. The effective scattering radius was obtained from fitting to the calculated total cross section at 100 keV. The radiation width Gg was based on the systematics of measured values for neighboring nuclides. Typical values of the parameters at 70 keV: S0 = 0.520e-4, S1 = 0.840e-4, S2 = 0.550e-4, Sg = 0.0303e-4, Gg = 0.075 eV, R = 5.301 fm. calculated 2200-m/s cross sections and res. integrals (barns) 2200 m/s res. integ. total 4.900 - elastic 3.300 - capture 1.600 0.728 *************************************************************** For JENDL-4.0, the unresolved resonance parameters were re-evaluated by the ASREP /19/ code so as to reproduce the total and capture cross sections given in JENDL3.3 in the energy region from 14 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 4.92400E+00 Elastic 3.31464E+00 n,gamma 1.60070E+00 7.27536E-01 ---------------------------------------------------------- (*) Integrated from 0.5 eV to 10 MeV. mf = 3 Neutron cross sections Below 14 keV, the capture and elastic scattering cross sections were assumed to be in 1/v form and constant, respectively. The capture cross section at 0.0253 eV was taken from Ref./3/, and the elastic scattering cross section was estimated by assuming r = 5.2 fm. Unresolved resonance parameters were given in the energy range from 14 keV to 100 keV. 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/4/ 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-natural total cross section by changing Ws and rso of Iijima-kawai potential/5/. The OMP's for charged particles are as follows: proton = Perey/6/ alpha = Huizenga and Igo/7/ deuteron = Lohr and Haeberli/8/ helium-3 and triton = Becchetti and Greenlees/9/ Parameters for the composite level density formula of Gilbert and Cameron/10/ were evaluated by Iijima et al./11/ 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 /12/. 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 based on Evaluated Nuclear Structure Data File (1987 version)/13/ and Nuclear Data Sheets/14/. no. energy(MeV) spin-parity gr. 0.0 0 + 1 0.6023 2 + 2 1.1306 4 + 3 1.5107 2 + 4 1.8027 3 - 5 1.8240 0 + 6 1.9513 3 + 7 1.9937 2 + Levels above 2.061 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/15/ and normalized to 1 milli-barn at 14 MeV. The gamma-ray strength function (2.71e-06) was adjusted to reproduce the capture cross section of 3.2 milli-barns at 70 keV measured by Musgrove et al./16/ for Ba-138. (the same cross section as Ba-138 was assumed.) 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 = 33 (n,n't) 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 (= 304.6) was estimated by the formula derived from Kikuchi-Kawai's formalism/17/ and level density parameters. Finally, the (n,p) and (n,alpha) cross sections were normalized to the following values at 14.5 MeV: (n,p) 1.40 mb (systematics of Forrest/18/) (n,alpha) 0.76 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 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 SYST A(1/MEV) T(MEV) C(1/MEV) EX(MEV) PAIRING --------------------------------------------------------------- 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 54-XE-138 * 1.684E+01 5.580E-01 3.365E-01 5.240E+00 1.880E+00 54-XE-139 * 1.849E+01 5.556E-01 2.542E+00 4.980E+00 1.120E+00 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 55-CS-139 * 1.696E+01 5.556E-01 2.545E+00 4.122E+00 7.600E-01 55-CS-140 1.484E+01 6.545E-01 1.053E+01 4.162E+00 0.0 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 56-BA-140 1.500E+01 6.930E-01 5.738E-01 7.244E+00 2.340E+00 56-BA-141 1.600E+01 7.010E-01 3.318E+00 7.141E+00 1.580E+00 --------------------------------------------------------------- syst: * = ldp's were determined from systematics. 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 4.553 for Ba-140 and 5.0 for Ba-141. References 1) Kawai, M. et al.: Proc. Int. Conf. on Nuclear Data for Science and Technology, Mito, p. 569 (1988). 2) Igarasi, S.: J. Nucl. Sci. Technol., 12, 67 (1975). 3) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. I, Part A", Academic Press (1981). 4) Iijima, S. et al.: JAERI-M 87-025, p. 337 (1987). 5) Iijima, S. and Kawai, M.: J. Nucl. Sci. Technol., 20, 77 (1983). 6) Perey, F.G: Phys. Rev. 131, 745 (1963). 7) Huizenga, J.R. and Igo, G.: Nucl. Phys. 29, 462 (1962). 8) Lohr, J.M. and Haeberli, W.: Nucl. Phys. A232, 381 (1974). 9) Becchetti, F.D., Jr. and Greenlees, G.W.: Polarization Phenomena in Nuclear Reactions ((Eds) H.H. Barshall and W. Haeberli), p. 682, the University of Wisconsin Press. (1971). 10) Gilbert, A. and Cameron, A.G.W.: Can. J. Phys., 43, 1446 (1965). 11) Iijima, S., et al.: J. Nucl. Sci. Technol. 21, 10 (1984). 12) Gruppelaar, H.: ECN-13 (1977). 13) ENSDF: Evaluated Nuclear Structure Data File (June 1987). 14) Nuclear Data Sheets, 51, 425 (1987). 15) Benzi, V. and Reffo, G.: CCDN-NW/10 (1969). 16) Musgrove, A.R. de L., et al.: Proc. Int. Conf. on Neutron Physics and Nucl. Data for Reactors, Harwell 1978, 449. 17) Kikuchi, K. and Kawai, M.: "Nuclear Matter and Nuclear Reactions", North Holland (1968). 18) Forrest, R.A.: AERE-R 12419 (1986). 19) Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999) [in Japanese].