14-Si- 28 JAEA EVAL-AUG07 K.Shibata, S.Kunieda
DIST-MAY10 20100127
----JENDL-4.0 MATERIAL 1425
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
07-08 Evaluated by K.Shibata and S.Kunieda.
10-01 Compiled by K.Shibata.
MF= 1 General information
MT=451 Descriptive data and directory
MF= 2 Resonance parameters
MT=151 Resolved resonance parameters
Resolved resonance region (Reich-Moore formula) : Below 1.75
MeV
The resolved resonance parameters were taken from the
ENDF/B-VII.0 data, which were evaluated by Leal et al./1/
The following comments were also taken from ENDF/B-VII.0:
------------------------------------------------------------
The following data were included in the analysis:
(1) Total cross section data of Perey et al. /2/ for
natural silicon, measured on the 47-m flight path at the
Oak Ridge Electron Linear Accelerator (ORELA)
(2) Transmission data of Harvey et al. /3/ for natural
silicon measured on the 200-m flight path at ORELA
(3) Total cross section data of Larson et al. /4/,
measured on the 80- and 200-m flight paths at ORELA
(4) 29Si-oxide /5/ and 30Si-oxide /6/ transmission
data of Harvey et al., measured on the 80-m ORELA flight
path
(5) Elastic scattering thermal cross section for 28Si
1.992+-0.006 barns from Mughabghab /7/. Capture
thermal cross section 0.169+-0.004 barns from Raman et
al. /8/. Values given by resonance parameters are
1.992 and 0.169 barns respectively.
------------------------------------------------------------
Thermal cross sections and resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 2.1612E+00
Elastic 1.9920E+00
n,gamma 1.6915E-01 8.4180E-02
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(*) Integrated from 0.5 eV to 10 MeV.
MF= 3 Neutron cross sections
MT= 1 Total cross section
Below 12.5 MeV, the cross sections were taken from the
JENDL-3.3 evaluation that was based on experimental data.
Above 12.5 MeV, the cross sections were calculated using
TNG /9/.
MT= 2 Elastic scattering cross section
Obtained by subtracting non-elastic cross sections from total
cross sections.
MT= 4,51-91 (n,n') cross section
Calculated with TNG code /9/. For MT=51, the cross sections
were replaced by the data measured by Sullivan et al./10/
below 4.15 MeV.
As for MT=91, the cross sections, which were calcuated with
TNG, were modified between 12 and 14.5 MeV.
MT= 16 (n,2n) cross section
Calculated with TNG code /9/.
MT= 22 (n,na) cross section
Calculated with TNG code /9/.
MT= 28 (n,np) cross section
Taken from JENDL-3.3.
MT=102 Capture cross section
Calculated with TNG code /9/.
MT=103 (n,p) cross section
Calculated from MT=600-649.
MT=107 (n,a) cross section
Calculated from MT=800-849.
MT=600-649 partial (n,p) cross section
Calculated with TNG code /9/. For MT=600,601, the cross
sections were replaced with the data measured by Bateman et
al./11/ between 5.513 and 8.973 MeV with a scaling factor of
0.5.
MT=800-849 partial (n,a) cross section
Calculated with TNG code /9/. For MT=800, the cross sections
were replaced with the data measured by Bateman et al./11/
between 5.853 and 7.986 MeV. Finally, the cross section of
MT=849 was increased to reproduce the total (n,a) cross
section of JENDL-3.3 above 11 MeV.
MF= 4 Angular distributions of emitted neutrons
MT= 2 Elastic scattering
Calculated with TNG code /9/. The shape elastic scattering
component was calculated using OPTMAN code./12/
MF= 6 Energy-angle distributions of emitted particles
MT= 16 (n,2n) reaction
Neutron and gamma-ray spectra calculated with TNG/9/.
MT= 22 (n,na) reaction
Neutron, alpha-particle, and gamma-ray spectra calculated with
TNG/9/.
MT= 28 (n,np) reaction
Neutron, proton, and gamma-ray spectra calculated with TNG/9/.
MT= 51-66 (n,n') reaction
Neutron angular distributions and discrete gamma-ray spectra
calculated with TNG/9/.
MT= 91 (n,n') reaction
Neutron spectra, and discrete-continuous gamma-ray spectra
calculated with with TNG/9/.
MT=102 (n,gamma) reaction
Gamma-ray spectra calcualted with TNG/9/.
MT=600-614 (n,p) reactions leading to discrete levels
Proton angular distributions and discrete gamma-ray spectra
calculated with TNG/9/.
MT=649 (n,p) reaction leading to continuum levels
Proton spectra and discrete-continuous gamma-ray spectra
calculated with TNG/9/.
MT=800-831 (n,a) reactions leading to discrete levels
Alpha-particle angular distributions and gamma-ray spectra
calculated with TNG/9/.
MT=849 (n,a) reaction leading to continuum levels
Alpha-particle spectra and discrete-continuous gamma-ray
spectra calculated with TNG/9/.
***************************************************************
* Nuclear Model Calculations with TNG Code /9/ *
***************************************************************
The description of the model calcualtions is given in Ref.13.
< Optical model parameters >
Neutrons and protons:
Coupled-channel optical model parameters /13/
Alphas:
The potential parameters were obtained using the code developed
by Kumar and Kailas./14/
< Level scheme of Si- 28 >
-------------------------
No. Ex(MeV) J PI
-------------------------
0 0.00000 0 +
1 1.77900 2 +
2 4.61790 4 +
3 4.97990 0 +
4 6.27620 3 +
5 6.69140 0 +
6 6.87880 3 -
7 6.88770 4 +
8 7.38060 2 +
9 7.41630 2 +
10 7.79900 3 +
11 7.93350 2 +
12 8.25870 2 +
13 8.32840 1 +
14 8.41330 4 -
15 8.54360 6 +
16 8.58870 3 +
The direct-reaction process was taken into accout for the 1st, 2nd
and 15th levels by the coupled-channel method.
< Level density parameters >
Energy dependent parameters of Mengoni-Nakajima /15/ were used.
----------------------------------------------------------
Nuclei a* Pair Esh T E0 Ematch Econt
1/MeV MeV MeV MeV MeV MeV MeV
----------------------------------------------------------
Si- 29 5.138 2.228 -3.404 1.964 0.625 10.099 7.521
Si- 28 4.489 4.536 -4.401 2.454 1.949 15.409 8.819
Si- 27 4.864 2.309 -2.076 1.916 0.076 10.784 5.262
Al- 28 4.508 0.000 -2.180 2.170 -3.293 10.786 3.012
Al- 27 4.142 2.309 -2.456 2.493 -2.390 16.024 6.948
Mg- 25 4.587 2.400 -0.869 1.901 -0.347 11.340 6.169
Mg- 24 3.964 4.899 -1.374 2.139 2.819 13.649 10.161
----------------------------------------------------------
References
1) L.C. Leal et al., Proc. Int. Conf. Nuclear Data for Science
and Technology, Trieste, 1997, Part I, 929 (1997).
2) F.G. Perey, T.A. Love, W.E. Kinney, Oak Ridge National
Laboratory report ORNL-4823 [ENDF-178] (1972).
3) J.A. Harvey, private communication (1996).
4) D.C. Larson, C.H. Johnson, J.A. Harvey, and N.W. Hill,
"Measurement of the neutron total cross section of silicon
from 5 eV to 730 keV," Oak Ridge National Laboratory report
ORNL/TM-5618 (1976)
5) J.A. Harvey, private communication (1996).
6) J.A. Harvey, W.M. Good, R.F. Carlton, et al., Phys.Rev.C
28, 24 (1983).
7) S.F. Mughabghab, M. Divadeenam, N.E. Holden, Neutron
Cross Sections, Vol. 1, Part A: Z=1-60, (Academic Press, NY,
1981).
8) S. Raman, et al., Phys.Rev.C 46, 972 (1992).
9) C.Y. Fu, ORNL/TM-7042 (1980); K. Shibata, C.Y. Fu, ORNL/TM-
10093 (1986).
10) N.B. Sullivan et al., Nucl. Sci. Eng., 70, 294 (1979).
11) F.B. Bateman et al., Phys. Rev., 55, 133 (1997).
12) E.Sh. Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).
13) K. Shibata, S. Kunieda, J. Nucl. Sci. Technol., 45, 123
(2008).
14) A. Kumar, S. Kailas, a computer code contained in RIPL-2,
Bhabha Atomic Research Center, private communication (2002).
15) A. Mengoni, Y. Nakajima, J. Nucl. Sci. Technol., 31, 151
(1994).