57-La-139 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G. DIST-MAY10 20091214 ----JENDL-4.0 MATERIAL 5728 -----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/. 93-11 JENDL-3.2 was made by JNDC FPND W.G. ***** modified parts for JENDL-3.2 ******************** (2,151) Resolved resonance parameters *********************************************************** 10-03 JENDL-4.0 was made. Resoloved resonance parameters were evaluated by T.Nakagawa. 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 15.0 keV Resonance parameters of JENDL-2/3/ were modified on the basis of the experimental data of Nakajima/4/ at 72.3 eV, and in the energy range from 617.2 to 2464 eV where 20 resonances were given. Resonance energies were mainly based on the data of JENDL-2 and supplemented with the experimental data of Nakajima. Neutron widths were derived from the neutron capture area data by using the average radiation width of 0.050 eV/3/. Total spin J of some resonances was tentatively estimated with a random number method. Assignment of neutron orbital angular momentum L is the same as the JENDL-2 evaluation. Two negative resonances were added so as to reproduce the thermal capture and scattering cross sections given by Mughabghab et al. For JENDL-3.2, these resonance parameters were modified so as to reproduce the area data measured at ORNL, by taking account of the correction factor of 1.0737 announced by Allen et al./5/. The upper boundary was changed from 25.9 keV to 15 keV. ************************************************************** The JENDL-3.3 evaluation was based on the data obtained by Shwe et al./24/, Morgenstern et al./25/, Hacken et al. /26/, Musgrove et al./27/, and Nakajima et al./4/ In JENDL-4, the data below 9 keV were replaced with the ones measured by Terlizzi et al./28/ Total spin J was determined by a random number method. The parameters for a negative resonance were adjusted so as to reproduce the averege of the measured thermal capture cross section 8.936+-0.035 b. ************************************************************** Unresolved resonance region : 15 keV - 100 keV The neutron strength function S0 and S1 were based on the compilation of Mughabghab et al., and S2 was calculated with optical model code CASTHY/6/. 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 compilation of Mughabghab et al. Typical values of the parameters at 70 keV: S0 = 0.780e-4, S1 = 0.400e-4, S2 = 0.500e-4, Sg = 2.04e-4, Gg = 0.055 eV, R = 5.455 fm. calculated 2200-m/s cross sections and res. integrals (barns) 2200 m/s res. integ. total 19.060 - elastic 10.130 - capture 8.930 11.8 *************************************************************** For JENDL-4.0, the unresolved resonance parameters were re-evaluated by the ASREP /29/ code so as to reproduce the total and capture cross sections given in JENDL3.3 in the energy region from 15 keV to 160 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 1.90109E+01 Elastic 1.00706E+01 n,gamma 8.94030E+00 1.16047E+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, by taking account of competing reactions, of which cross sections were calculated with PEGASUS/7/ standing on a preequilibrium and multi-step evaporation model. The OMP's for neutron given in Table 1 were determined so as to reproduce the La-139 total cross sections measured by Foster and Glasgow/8/, Islam et al./9/, Nishimura et al./10/ and so on. 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 gr. 0.0 7/2 + 1 0.1658 5/2 + 2 1.2060 1/2 + 3 1.2191 9/2 + 4 1.2566 5/2 + 5 1.3813 7/2 + 6 1.4205 7/2 + 7 1.4390 11/2 - 8 1.4764 7/2 + 9 1.5363 7/2 + 10 1.5582 3/2 + 11 1.5782 9/2 + 12 1.6831 7/2 + Levels above 1.75 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/19/ and normalized to 1 milli-barn at 14 MeV. The gamma-ray strength function (2.06e-04) was adjusted to reproduce the capture cross section of 38 milli-barns at 30 keV measured by Musgrove et al./20/ 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 =106 (n,he3) 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 (= 322.9) was estimated by the formula derived from Kikuchi-Kawai's formalism/21/ 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) 5.00 mb (recommended by Forrest/22/) (n,alpha) 2.50 mb (measured by Woelfle+/23/) mt = 251 mu-bar Calculated with CASTHY/6/. 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 = 6.874 A0 = 0.62 WS = 2.95+0.789E RS = 7.081 AS = 0.35 VSO= 7.0 RSO= 6.874 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 --------------------------------------------------------------- 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 57-LA-137 1.558E+01 6.210E-01 3.521E+00 4.624E+00 7.000E-01 57-LA-138 1.450E+01 6.310E-01 7.202E+00 3.634E+00 0.0 57-LA-139 1.380E+01 6.500E-01 1.653E+00 4.468E+00 8.500E-01 57-LA-140 1.558E+01 5.900E-01 7.912E+00 3.425E+00 0.0 --------------------------------------------------------------- Spin cutoff parameters were calculated as 0.146*sqrt(a)*a**(2/3). 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