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93-Np-237 LANL EVAL-APR90 P.YOUNG, E.ARTHUR, F.MANN
DIST-JAN09 20090105
----JEFF-311 MATERIAL 9346
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
*************************** JEFF-3.1.1 *************************
** **
** Original data taken from: JEFF-3.0 Modified **
** Modification: 8 delayed neutron groups, NEA **
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2008-12 NEA/OECD (Rugama) 8 delayed neutron groups
Ref: JEFDOC-976 (Wilson and England, Prog Nucl Eng 41,71(2002)
***************************** JEFF-3.0 ***********************
DATA TAKEN FROM :- ENDF/B-VI rel.4 (DIST-SEP91 REV1-JUL91)
(n,xn) data from JEF-2.2
MT=2 recalculated to preserve MT=1
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MOD1 OF ENDF/B-VI
The following revisions were made for MOD1 of ENDF/B-VI:
1. MF=4,MT=19,20,21,38 - Angular distribution data (isotropic)
removed because no energy spectra available.
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SUMMARY OF ENDF/B-VI EVALUATION
Principal evaluators: P.G.Young, E.D.Arthur, F.M.Mann, with
significant contributions from D.G.Madland, M.Bozoian, and
R.E.MacFarlane.
The evaluation below about 8 keV is based on the analysis of
Derrien (De80) and is the same as JEF-2 (De89).
The evaluation above 8 keV is based on a detailed theoretical
analysis utilizing the available experimental data. Coupled
channel optical model calculations with the ECIS code (Ra70)
were used to provide the total, elastic, and inelastic cross
sections to the first 3 members of the ground state rotational
band, as well as neutron elastic and inelastic angular distri-
butions to the rotational levels. The optical potential of
Lagrange (Ha80) was extended to higher energies based on ENDF/B-
VI analyses for U235, U238, Pu239. The ECIS calculation was also
used to provide neutron transmission coefficients. Hauser-
Feshbach statistical theory calculations were carried out with
the GNASH (Ar88, Yo77) and COMNUC (Du70) code systems, including
preequilibrium and fission. DWBA calculations were performed
with the DWUCK code (Ku70) for several vibrational levels, using
B(El) values inferred from (d,d') data on various actinides, as
well as Coulomb excitation measurements. Based on systematics,
fictitious l=2 and l=3 vibrational states were located near
excitation energy 1 MeV, containing all the vibrational
strength.
A summary of the theoretical methods and evaluation up to
5 MeV is given in reference Ar85.
**********MF=1 Descriptive and Nubar Information*****************
MT=452 Total Nubar. Sum of MT=455 and 456.
MT=455 Delayed Neutron Yields. Based on the analysis and
evaluation of England for ENDF/B-VI (En89).
MT=456 Prompt Neutron Yields. Based on smooth curve through
experimental data of Ma83,Ve78,Fr82, after renormaliza-
tion for ENDF/B-VI standards. Results agree closely
with values from Madland-Nix theory (Ma84).
MT=458 Energy from Fission. Based on revised Sher (Sh83).
**********MF=2 Resonance Region**********************************
MT=151 Resolved Resonance Parameters. Derrien evaluation (De80,
De89) used for resolved resonance region, which spans
the range 1.0E-5 to 150 eV.
**********MF=3 Smooth Cross Sections*****************************
MT=1 Neutron Total Cross Section. Derrien evaluation (De80,
De89) used from 1.0E-5 eV to 0.008 MeV. Above 0.008 MeV,
coupled channel optical model calculations (ECIS code)
with modified Lagrange (Ha80) potential used as prior
in a covariance analysis of measurement by Lisowski et
al. from 3 to 20 MeV (Li90).
MT=2 All Energies, based on subtraction of MT=4,16,17,18,37,
and 102 from MT=1.
MT=4 Sum of MT=51-91
MT=16 GNASH Hauser-Feshbach statistical/preequilibrium calc.
For 9 MeV and below, the experimental data of Kornilov et
al. (Ko85) are used.
MT=17 GNASH Hauser-Feshbach statistical/preequilibrium calc.
MT=18 Fission Cross Section. Derrien evaluation (De80,De89)
used to 0.8 MeV. Empirical fit mainly to experimental
data of Lisowski et al.(Li88) and Meadows (Me83,Me88)
in the energy range 0.9-20 MeV, but with consideration
of the data of Te86, Ka85, Ca82, Wh67, Za84, and Va82.
MT=19 (n,f) first-chance fission cross section.
Ratio of first-chance to total fission obtained from
GNASH calculations.
MT=20 (n,nf) second-chance fission cross section.
Ratio of second-chance to total fission obtained from
GNASH calculations.
MT=21 (n,2nf) third-chance fission cross section.
Ratio of third-chance to total fission obtained from
GNASH calculations.
MT=37 GNASH Hauser-Feshbach statistical/preequilibrium calc.
MT=38 (n,3nf) fourth-chance fission cross section.
Ratio of fourth-chance to total fission obtained from
GNASH calculations.
MT=51,53 Threshold to 20 MeV, coupled-channel optical model
calculations (7/2+ and 9/2+ members of the K=5/2 ground
state rotational band) using the ECIS code. Compound
nucleus contributions, obtained from COMNUC calcula-
tions, are also included.
MT=52,54-79 Threshold to 6.0 MeV, compound nucleus reaction
theory (COMNUC code) calculation with width fluctuation
corrections. Cross section assumed zero above 6 MeV.
MT=80 Threshold to 20 MeV, distorted wave Born approximation
(DWUCK code) calculations with the DWUCK code for
l=2 vibrational states. Systematics in actinide region
used to infer B(E2) values for normalizing DWBA
calculations.
MT=81 Threshold to 20 MeV, distorted wave Born approximation
(DWUCK code) calculations with the DWUCK code for
l=3 vibrational states. Systematics in actinide region
used to infer B(E3) values for normalizing DWBA
calculations.
MT=91 GNASH Hauser-Feshbach statistical/preequilibrium calc.
Note that the MT=80,81 vibrational states lie in the
MT=91 continuum region.
MT=102 Radiative Capture. From 1.0e-5 eV to 5 MeV, based on
Derrien (De80,De89) evaluation, which follows exp.
data of Weston (We81). Above 5 MeV, ENDF/B-V evaluation
is retained.
**********MF=4 Neutron Angular Distributions********************
MT=2 Elastic scattering angular distribution based on ECIS
coupled-channel calculations, with a compound elastic
component from COMNUC included below 6 MeV.
MT=51-55,57 Thres. to 20 MeV, Coupled-channel optical model
calculations plus compound-nucleus contributions.
MT=52,54-79 Threshold to 6.0 MeV, COMNUC compound
nucleus reaction theory calculation with width fluctua-
tions. Cross sections assumed zero from 6-20 MeV.
MT=80,81 Thres. to 20 MeV, Distorted wave Born approximation
calculations with DWUCK code.
************MF=5 Neutron Energy Distributions*******************
MF=18 Composite neutron energy distributions from fission.
Based on calculations by D.Madland (Ma84) using Madland-
Nix formalism. The calculations include the first-,
second-, and third-chance fission neutron components.
The data are represented using LAW 12.
MT=455 Provided by Tal England (En89).
************MF=6 Correlated Energy-Angle Distributions**********
MT=16 GNASH Hauser-Feshbach statistical/preequilibrium calc.
Updated Kalbach-Mann systematics used for specifying
neutron distributions (Ka87). Only neutrons given.
MT=17 GNASH Hauser-Feshbach statistical/preequilibrium calc.
Updated Kalbach-Mann systematics used for specifying
neutron distributions (Ka87). Only neutrons given.
MT=37 GNASH Hauser-Feshbach statistical/preequilibrium calc.
Updated Kalbach-Mann systematics used for specifying
neutron distributions (Ka87). Only neutrons given.
MT=91 GNASH Hauser-Feshbach statistical/preequilibrium calc.
Updated Kalbach-Mann systematics used for specifying
neutron distributions (Ka87). Only neutrons given.
****************MF=8 Radioactive Nuclide Data*******************
MT=16 Information on ground and 77-keV isomeric states.
***********MF=8 Multiplicities for Radioactive Nuclides*********
MT=16 Branching ratios calculated by Gardner & Gardner (Ga89)
were used.
****************MF=12,13,14,15 Photon Production****************
The evaluation of photon production was performed by Fred Mann
(WHC). Photon production for discrete inelastic scattering
(mt = 51 - 79) uses transition probability arrays. Gamma-ray
branching for the excited states of Np237 was obtained from the
Nuclear Data Sheets. Photon production for neutron capture was
taken from the ENDF/B-VI evaluation of Pu-240 (which has a similar
Q value). Photon production for fission was taken from the
ENDF/B-VI evaluation of U235. The photon spectrum for non elastic
events (mt=3) was taken from the ENDF/B-VI evaluation of U235.
The photon yield was adjusted to conserve energy.
******************References************************************
Ar85 E.D.Arthur et al., LA-10288-PR (1985)p.13.
Ar88 E.D.Arthur, LA-UR-88-382 (1988).
Ca82 M.Cance et al., Antwerp Nuc.Data Conf., p.51 (1982).
De80 H.Derrien, INDC(FR)-42 (1980).
De89 H.Derrien, personal communication (July 7, 1989).
Du70 C.L.Dunford, AI-AEC-12931 (1970).
En89 M.C.Brady & T.R.England,NSE 103,129(1989).
Fr82 J.Frehaut et al., Int.Conf.on Nucl.Data for Sci.& Tech.,
Antwerp, 6-10 Sept.1982, p.78.
Ga89 G.Gardner & M.Gardner, Personal Communication (1989) and
UCAR-10062-83/1 (1983) p.51.
Ha80 G.Haouat,Ch.Lagrange, et al., Nucl.Cross Sect. for Tech.,
Knoxville,Tenn., Oct. 22-26, 1979.
Ka85 K.Kanda et al., JAERI-M-85-035, 220 (1985).
Ka87 C.Kalbach, LA-UR-87-4139 (1987) [to be pub.in Phys.Rev.C].
Ko85 N.V.Kornilov et al., Sov.J.At.En.58,131(1985).
Ku70 P.D.Kunz, DWUCK: A Distorted-Wave Born Approximation
Program, unpublished report.
Li88 P.W.Lisowski et al., Nucl.Data for Sci.& Tech. Conf., Mito
Japan, May 30 - June 3, 1988.
Li90 P.W.Lisowski et al., Personal Communication.
Ma83 V.V.Malinovsky et al., YK 1,50 (1983).
Ma84 D.G.Madland, personal communication (1984).
Me83 J.W.Meadows et al., Nuc.Sci.Eng.85,271(1983).
Me88 J.W.Meadows et al., Ann.Nuc.En.15,421(1988).
Ra70 J.Raynal,IAEA SMR-9/8 (1970).
Sh83 R.Sher & Beck, EPRI NP1771/81 + Rev1/83 + personal
communication to Magurno (Feb., 1983).
Ve78 L.Veeser et al., Phys.Rev.C17, 385 (1978).
Te86 H.Terayama, NETU-47 (1986).
We81 L.Weston et al., Nuc.Sci.Eng.79,184(1981).
Wh67 P.White, Jour.Nuc.Ener.21, 671 (1967).
Va82 M.Varnagy, Nuc.Inst.Meth. 196, 465 (1982).
Za84 K.Zasadny, Tr.Am.Nuc.Soc. 47, 425 (1984).
Yo77 P.G.Young & E.D.Arthur, LA-6947 (1977).
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