12-Mg- 25 DEC,NEDAC EVAL-MAR87 M.HATCHYA(DEC),T.ASAMI(NEDAC) DIST-MAY10 20090828 ----JENDL-4.0 MATERIAL 1228 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT =========================================================== The data were taken from JENDL-3.3. =========================================================== HISTORY 87-03 New evaluation was made for JENDL-3. 87-03 Compiled by T.Asami. 01-04 Gamma-ray production data were added. Compiled by K.Shibata. ***** modification for JENDL-3.3 ****************************** (1,451) Updated. (3,251) Deleted. (4,2) Transformation matrix deleted. (5,16-91) INT=22. (12,16-107) Added. (14,16-107) Added. (15,16-107) Added. ***************************************************************** mf=1 General information mt=451 Descriptive data and dictionary mf=2 Resonance parameters mt=151 Resolved resonance parameters Resolved parameters for MLBW formula were given in the energy region from 1.0e-5 eV to 220 keV. Parameters were taken from the recommended data of BNL/1/ and modified for some levels so as to reproduce the experi- mental total cross section of the element Mg. The data for a negative resonance were added so as to reproduce the recommended thermal cross sections for capture and scatter- ing/1/. The data for some levels were modified so that the calculated total cross sections of the element Mg were fitted to the experimental data of Hibdon/2/ and Singh/3/. The scattering radius was assumed to be 4.9 fermi. Calculated 2200 m/sec cross sections and resonance integrals are as follows: 2200 m/s cross section(b) res. integral(b) elastic 2.60 capture 0.190 0.0989 total 2.79 mf=3 Neutron cross sections Below 220 keV, zero background cross section was given and all the cross-section data are reproduced from the evaluated resolv- ed resonance parameters with MLBW formula. Above 220 keV, the total and partial cross sections were given pointwise. mt=1 Total Optical and statistical model calculation was made with the casthy code/2/. The optical potential parameters used are: V = 49.68, Vso = 7.12 (MeV) Ws = 7.76 - 0.5*En, Wv = 0 (MeV) r = 1.17, rs = 1.09, rso = 1.17 (fm) a = 0.6, aso = 0.6, b = 0.69 (fm) mt=2 Elastic scattering Obtained by subtracting the sum of the partial cross sections from the total cross section. mt=4, 51-67, 91 Inelastic scattering Calculated with casthy/4/, taking account of the contribution from the competing processes. The direct component was calculated with the dwuck/5/. The level data used in the above two calculations were taken from ref./6/ as follows: mt level energy(MeV) spin-parity 0.0 5/2+ 51 0.5851 1/2+ 52 0.9748 3/2+ 53 1.6118 7/2+ 54 1.9647 5/2+ 55 2.5638 1/2+ 56 2.7377 7/2+ 57 2.8011 3/2+ 58 3.4052 9/2+ 59 3.4137 3/2- 60 3.9078 5/2+ 61 3.9707 7/2- 62 4.0596 9/2+ 63 4.2770 1/2- 64 4.3594 3/2+ 65 4.7114 9/2+ 66 4.7220 1/2- 67 5.0122 7/2+ Levels above 8.0 MeV were assumed to be overlapping. mt=16, 22, 28, 103, 107 (n,2n), (n,na), (n,np), (n,p), (n,a) Calculated with the gnash code/7/ using the above optical model parameters The (n,p) cross sections were normalized to the experimental data at 14 MeV of Bormann/8/. mt=102 Capture Calculated with the casthy code/4/ and normalized to 4.7 mb at 30 keV. mf=4 Angular distributions of secondary neutrons mt=2 Calculated with the casthy code/4/. mt=51-67 Calculated with the casthy code/4/ and the dwuck code/5/. mt=91 Calculated with the casthy code/4/. mt=16, 22, 28 Isotropic in the laboratory system. mf=5 Energy distributions of secondary neutrons mt=16, 22, 28, 91 Calculated with the gnash code/7/. mf=12 Photon multiplicities and transition probabilities mt=16,22,28,91,103,107 Calculated with gnash. mt=51-67 Stored under option-2 (transition probability array). mt=102 Calculated with casthy. mf=14 Photon angular distributions mt=16,22,28,51-67,91,102,103,107 Isotropic. mf=15 Continuous photon energy spectra mt=16,22,28,91,103,107 Calculated with gnash. mt=102 Calculated with casthy. References 1) Mughabghab S.F. and Garber D.I. :"Neutron cross sections", Vol. 1, Part B (1984). 2) Hibdon C.T. : taken from exfor (1969). 3) Singh U.N. et al. : Phys. Rev. C10, 2150 (1974). 4) Igarasi S. : J. Nucl. Sci. Tech. 12, 67 (1975). 5) Kunz P.D. : unpublished. 6) ENSDF(Evaluated Nuclear Structure Data File) 7) Young P.G. and Arthur E.D. : LA-6947 (1977). 8) Bormann M. et al. : 1966 Paris Conf. Vol.1, 225 (1967).