12-MG- 25 DEC,NEDAC EVAL-MAR87 M.HATCHYA(DEC),T.ASAMI(NEDAC)
DIST-MAR02 REV2-MAY01 20010517
----JENDL-3.3 MATERIAL 1228
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
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).