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24-Cr- 54 ORNL EVAL-NOV89 HETRICK,D.C. & N.M. LARSON,FU
ORNL/TM DIST-JAN09 20090105
----JEFF-311 MATERIAL 2437
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
*************************** JEFF-3.1.1 *************************
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** Original data taken from: JEFF-3.1 **
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***************************** JEFF-3.1 *************************
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** Original data taken from: JEFF-3.0 **
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***************************** JEFF-3.0 *************************
DATA TAKEN FROM :- ENDF/B-VI.3 (DIST-JUN90)
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ENDF/B-VI MOD 3, October 1997 (V. McLane, NNDC)
1. Residual nucleus and AWR corrected in File 6, MT=16.
2. File 1 comments revised.
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ENDF/B-VI MOD 2, July 1991.
1. The secondary particle distributions for MF=6,MT=51-54 were
corrected to center-of-mass, from laboratory coordinates.
2. The elastic transformation matrix was removed.
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ENDF/B-VI MOD 1 Evaluation, November 1989.
D. Hetrick, D. Larson, N. Larson, C. Fu, ORNL
This work employed the Hauser-Feshbach code TNG [1,2,3].
The TNG code provides energy and angular distributions of
particles emitted in the compound and pre-compound reactions,
ensures consistency among all reactions, and maintains energy
balance. Details pertinent to the contents of this evaluation
will be published at a later date.
Description of files -------------------------------------------
(MF-MT)
1-451 General information, references, and definitions.
2-151 Resonance parameters; used to provide the total,
scattering, and capture cross sections from 1.E-5 eV to
900 keV. The resonance parameters are taken from Agrawal
et al. [4] and Allen and Musgrove [5], and readjusted to
attempt to match the thermal values. A background file
in 3-1 is used from 11-900 keV.
Note that the flag has been set to allow user calculation
of the angular distributions from the R-Matrix resonance
parameters, if the user wants angular distributions on
a finer energy grid than given in 4-2.
3-1 Total cross section; given by resonance parameters up to
900 keV with negative energy resonances adjusted to give
measured thermal scattering and capture cross sections.
Above 900 keV, isotopic data used to 4.0 MeV from Harvey
and Agrawal [6] and from 4.0-20.0 MeV high resolution
natural Cr transmission measurements were used from
Larson et al. [7].
3-2 Elastic scattering cross sections were obtained by
subtracting the nonelastic from the total
3-3 Nonelastic cross section; sum of 3-4, 3-16, 3-102,
3-103, and 3-107.
3-4 Total inelastic cross section; sum of 3-51, 3-52, ...
...,3-54, and 3-91
3-16 (n,2n) cross section; calculated by the TNG code [1,2,3].
No data available.
3-51 to 3-54 Inelastic scattering exciting levels; results are
from TNG [1,2,3].
3-91 Inelastic scattering exciting the continuum; Calculated
by TNG.
3-102 (n,g) capture cross section; given by resonance parameters
up to 900 keV; from 900 keV to 20 MeV, TNG calculations
were used but normalized to measured average capture
between 100 keV and 900 keV. TNG calculations included a
precompound component and weighted cross sections from
all isotopes of Cr give 0.82 mb at 14.5 MeV, in agreement
with the measurement of 0.75 mb for natural Cr.
3-103 (n,p) cross section; calculated by the TNG code [1,2,3]
Calculations agree well with data.
3-107 (n,a) cross section; calculated by the TNG code [1,2,3].
Calculations agree well with data.
4-2 Angular distributions of secondary neutrons for elastic
scattering; from ENDF/B-V.
If desired, angular distributions can be calculated by
the user on a finer energy grid from the R-Matrix
resonance parameters in 2-151.
6-16 (n,2n) reaction; includes simple constant yields for the
neutron and 53Cr residual, and energy dependent yield
based on TNG calculated gamma-ray spectra for the gamma
ray; TNG calculated normalized distributions are given
for each product. Isotropy is assumed.
6-51 through 6-54 Inelastic scattering exciting levels;
assumed isotropic.
6-91 Inelastic scattering exciting the continuum; includes
simple constant yields for the neutron and 54Cr residual
and energy dependent yield based on TNG calculated gamma-
ray spectra for the gamma ray; TNG calculated normalized
distributions are given for each. Isotropy is assumed.
6-103 (n,p) reaction; includes simple constant yields for p
and 54V residual, and energy dependent yield based on
calculated gamma-ray spectra for gamma ray; calculated
normalized distributions are given for each product.
Isotropy is assumed.
6-107 (n,a) reaction; includes simple constant yields for a
and 51Ti residual, and energy dependent yield based on
calculated gamma-ray spectra for gamma ray; calculated
normalized distributions are given for each product.
Isotropy is assumed.
12-51 through 12-54 Branching ratios for the levels are given.
12-102 (n,g) capture; TNG calculated.
14-51 through 14-54 and 14-102 Gamma ray angular distributions
assumed to be isotropic.
15-102 (n,g) capture; TNG calculated.
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Uncertainty files
An LB=8 section is included for all non-derived files as
required by ENDF/B-VI.
33-1 Uncertainties are derived from 1.E-5 to 100 eV. From 100
eV to 20 MeV they are explicit, using LB=0,1 and 8.
33-2 From 1.E-5 to 100 eV, uncertainties are explicit, based
upon thermal uncertainty and other data. From 100 eV to
20 MeV the files are derived.
33-3 From 1.E-5 to 900 keV uncertainties are derived. From
900 keV to 20 MeV uncertainties are explicit, using LB=1
and 8.
33-4 Uncertainties are all derived.
33-16 Uncertainties for (n,2n) are explicit, estimated from TNG.
33-51 through 3-91 Uncertainties for inelastic scattering are
explicit, based on data and calculation uncertainties.
33-102 Uncertainties are explicit, based on thermal data at low
energies, and calculated results above 900 keV.
33-103 Uncertainties estimated from TNG.
33-107 Uncertainties estimated from TNG.
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REFERENCES:
[1] C.Y. Fu, "A consistent nuclear model for compound and
precompound reactions with conservation of angular
momentum," Oak Ridge National Laboratory report ORNL/TM-7042
(1980) and Nucl.Sci.Eng. 100, 61 (1988).
[2] C.Y Fu, "Development and application of multi-step
Hauser-Feshbach/pre-equilibrium model theory," Neutron Cross
Sections from 10 to 50 MeV, Symp., Upton, N.Y., May 12-14,
1980, Brookhaven National Laboratory report BNL-NCS-51425
(1980) p.675.
[3] K. Shibata and C.Y. Fu, "Recent Improvements of the TNG
Statistical Model Code", Oak Ridge National Laboratory
report ORNL/TM-10093 (1986).
[4] H.M. Agrawal, J.B. Garg, and J.A. Harvey, Phys. Rev. C 30,
1880 (1984).
[5] B.J. Allen and A.R. De L. Musgrove, "S-wave Resonance
Parameters in the Structural Materials," Neutron Data of
Structural Materials for Fast Reactors, Proc. Specialists'
Meeting, Geel, Belgium, Dec. 5-8, 1977.
[6] J.A. Harvey and H.M. Agrawal, private comm., 1988.
[7] D.C. Larson, J.A. Harvey, and N.W. Hill, private comm.,
1988; data available at NNDC.
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