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24-Cr- 50 ORNL EVAL-NOV89 HETRICK,D.C. & N.M. LARSON,FU
DIST-JAN09 20090105
----JEFF-311 MATERIAL 2425
-----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 for 49Cr 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=51-56 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
792 keV. A small contribution in file 3-102 is added for
capture from 325 to 792 keV (see 3-102 below). The
resonance parameters are taken from Brusegan [4] with
help from brusegan et al. (private comm., 1988), and are
adjusted to give correct thermal values. The parameters
were also adjusted to the data of J.A. Harvey and H.M.
Agrawal [8], and a background file is given in 3-1 from
30 to 792 keV. Note that the flag has been set to allow
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
792 keV with negative energy resonances adjusted to give
measured thermal scattering and capture cross sections
(see description for 3-102, below). Above 792 keV,
isotopic data used to 4.0 MeV [8] and from 4.-20.0 MeV
high resolution natural Cr transmission measurements were
used, see Larson et al. [9].
3-2 Elastic scattering cross section; obtained by subtracting
the nonelastic from the total.
3-3 Nonelastic cross section; sum of 3-4, 3-16, 3-22,
3-28, 3-102, 3-103, 3-104, and 3-107.
3-4 Total inelastic cross section; sum of 3-51, 3-52, ...
...,3-56, and 3-91
3-16 (n,2n) cross section; taken from the measurements of
Ghorai et al. [5] and Ikeda et al. [6].
3-22 (n,na) cross section; calculated by the TNG code [1,2,3];
no data available other than a emission.
3-28 (n,np) cross section; calculated by the TNG code [1,2,3].
Little data available; 3-28 added to 3-103 agrees well
with sparse p-emission data.
3-51 To 3-56 inelastic scattering exciting levels; results are
from TNG [1,2,3].
3-91 Inelastic scattering exciting the continuum; TNG
calculated.
3-102 (n,g) capture cross section; given by resonance parameters
up to 792 keV and from 792 keV to 20 MeV, TNG calculations
were used but normalized to measured average capture
between 100 keV and 792 keV. A small contribution to be
added to 2-151 is given from 325 to 792 keV due to
incomplete experimental capture resonance information.
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].
Little data available; see 3-28 above.
3-104 (n,d) cross section; shape of (n,p) cross section used;
normalized to available data [7].
3-107 (n,a) cross section; calculated by the TNG code [1,2,3]
3-22 added to 3-107 agrees well with sparse alpha-
emission 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 49Cr 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.
6-22 (n,na) reaction; includes simple constant yields for the
neutron, alpha, and 46Ti residual, and energy dependent
yield based on tng calculated gamma-ray spectra for the
gamma ray; calculated normalized distributions are given
for each product. Isotropy is assumed.
6-28 (n,np) reaction; includes simple constant yields for the
neutron and 49V residual, and energy dependent yield
based on TNG calculated gamma-ray spectra for the gamma
ray; calculated normalized distributions are given for
each product. Isotropy is assumed. (n,xp) d-d emission
data used to benchmark the calculation.
6-51 through 6-56 inelastic scattering exciting levels;
assumed isotropic.
6-91 Inelastic scattering exciting the continuum; includes
simple constant yields for the neutron and 50Cr 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 50V 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. (n,xp) d-d emission data
used to benchmark the calculation.
6-107 (n,a) reaction; includes simple constant yields for alpha
and 47Ti 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. (n,xa) d-d emission data used to
benchmark the calculation.
12-51 through 12-56 branching ratios for the levels are given.
12-102 (n,g) capture; TNG calculated.
14-51 through 14-56 and 14-102 gamma ray angular distributions;
assumed to be isotropic.
15-102 (n,g) capture; TNG calculated.
----------------------------------------------------------------
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 792 keV uncertainties are derived. From
792 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.
33-22 Uncertainties for (n,na) are explicit, estimated from TNG.
33-28 Uncertainties for (n,np) 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 792 keV.
33-104 Uncertainties estimated, based on data.
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] A. Brusegan, R. Buyl, F.Corvi, L. Mewissen, F. Poortmans,
G. Rohr, R. Shelley, T. van der Veen, I. van Marcke, "High
Resolution Neutron Capture and Total Cross Section
Measurements of 50Cr, 52CR, and 53Cr," Proc. Int. Conf.
Santa Fe, NM, May 13-17, 1985 p. 633.
[5] S.K. Ghorai, J.R. Williams, and W.L. Alford, J.Phys.G 13,
405 (1987).
[6] Y. Ikeda, C. Konno, K. Oishi, T. Nakamura, H. Miyade, K.
Kawade, H. Yamamoto, and T. Katoh, report JAERI 1312 (1988).
[7] S.M. Grimes, R.C. Haight, K.R. Alvar, H.H. Barschall, and
R.R. Borchers, Phys.Rev. C19, 2127 (1979).
[8] J.A. Harvey and H.M. Agrawal, private communication (1988).
[9] D.C. Larson, J.A. Harvey, and N.W. Hill, private comm.
(1988); data available at NNDC.
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