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13-Al- 27 LANL EVAL-FEB97 M.B.CHADWICK & P.G.YOUNG
Ch97,Ch99 DIST-JAN09 20090105
----JEFF-311 MATERIAL 1325
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
*************************** JEFF-3.1.1 *************************
** **
** Original data taken from: JEFF-3.1 **
** **
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***************************** JEFF-3.1 *************************
** **
** Original data taken from: JEFF-3.0 **
** **
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***************************** JEFF-3.0 ***********************
DATA TAKEN FROM :- ENDF/B (DIST-AUG99)
New evaluation performed at ORNL (see comments below)
******************************************************************
File 2
MT=151 Resonance parameter evaluation was done by Derrien,
Leal, Guber, Larson, and Wright using the multilevel R-matix
analysis code SAMMY [La98]. The resonance evaluation were done
in the energy range from 0 to 850 keV. This evaluation includes
a new format to permit the representation of the resonance spin
channel. It is defined according to AJ=-J or AJ=+J, which allows
to distinguish the J values formed through s = 1 +/- 1/2 channel
spin. This new feature has been included in the SAMMY and NJOY
codes.
The evaluation included high resolution transmission data [Gu00],
capture cross section data [Ro99] measured at the Oak Ridge
Electron Linear Accelerator (ORELA), in addition to other
experimental data.
Experimental Data Included in the Evaluation
--------------------------------------------
1. Two transmission data measured at ORNL/ORELA in the energy
range of 0.5 eV to 400 keV in the 80-meter flight-path with
thicknesses of 0.01892 at/b and 0.1513 at/b, respectively[Gu99].
2. Two transmission data measured at Geel/Belgium in the energy
range of 200 keV to 850 keV in the 400-meter flight-path with
thicknesses of 0.05334 at/b and 0.01920 at/b, respectively[Ro94].
3. One transmission data measured ant ORNL/ORELA in the energy
range 200 keV to 850 keV in the 47-meter flight-path with
thickness 0.7639 at/b[Pe72].
4. One capture measurement in the energy range 100 eV to 670 keV
in the 40-meter flight-path[Gu99].
5. Thermal values (0.0253 eV) for total, capture and scattering
were obtained from the literature.
Thermal Cross Sections (0.0253 eV)
----------------------------------
ENDF/B-VI.5 ORNL
----------- ----
Total 1.60 barns 1.68 barns
Elastic 1.37 barns 1.45 barn
Capture 0.232 barns 0.233 barns
Res. Int. 0.134 barns 0.131 barns
Comparison of Average Cross Section with ENDF/B-VI.5
(Calculations done with NJOY)
Energy (keV) Total(barns) Capture (barns)
----------- -------------- ----------------
ENDF ORNL ENDF ORNL
------ ------ ------ ------
1.0e-5 - 1.0e-3 1.417 1.496 6.718e-2 6.753e-2
1.0e-3 - 0.1 1.354 1.428 6.720e-3 6.699e-3
0.1 - 0.5 1.350 1.408 2.718e-3 2.173e-3
0.5 - 1.0 1.349 1.381 1.985e-3 1.216e-3
1.0 - 100.0 5.385 5.228 4.376e-3 3.370e-3
100.0 - 200.0 5.286 5.814 1.994e-3 1.376e-3
200.0 - 500.0 3.925 4.130 8.734e-4 6.180e-4
500.0 - 800.0 3.912 4.003 8.585e-4 3.093e-4
Reference:
---------
[La98] N. M. Larson, Updated User Guide for SAMMY: Multilevel
R-Matrix Fits to Neutron Data Using Bayes' Equations,
ORNL/TM-9179/R4 (December 1998). See also ORNL/TM-9170/R5.
[Gu99] K. H. Guber et. al., "Neutron Capture and Neutron Total
Cross Section Measurements for 27Al at the Oak Ridge Electron
Linear Accelerator," 10th Int. Symp. Capture Gamma-Ray
Spectroscopy and Related Topics, Los Alamos, New Mexico,
August 30 to September/1999.
[Ro94] G. Rohr et al.,"Resonance Analysis Parameters for 27Al + n
from Very High Resolution Measurements," Proc. Int. Conf. Nuclear
Data for Science and Technology, Gatlinburg, Tennessee, May/1994
[Pe72] F. G. Perey, T. A. Love and W. E. Kenney,"A Test of
Neutron Total Cross Section Evaluations from 0.2 eV To 20 MeV for
C, O, Al, Si, Ca, Fe and SiO2, ORNL-4823, ENDF-8 (1972).
******************************************************************
ENDF/B-VI MOD 3 Evaluation, February 1997, M.B. Chadwick and
P.G. Young, LANL
Los Alamos LA150 Library, produced with FKK/GNASH/GSCAN code
in cooperation with ECN Petten.
This evaluation provides a complete representation of the
nuclear data needed for transport, damage, heating,
radioactivity, and shielding applications over the incident
neutron energy range from 1.0E-11 to 150 MeV. The discussion
here is divided into the region below and above 20 MeV.
INCIDENT NEUTRON ENERGIES < 20 MeV
Below 20 MeV the evaluation is based completely on the ENDF/B-
VI.1 (Release 3) evaluation by Young [Yo94].
INCIDENT NEUTRON ENERGIES > 20 MeV
The ENDF/B-VI Release 3 evaluation extends to 40 MeV and
includes cross sections and energy-angle data for all
significant reactions. The present evauation utilizes a more
compact composite reaction spectrum representation above 20 MeV
in order to reduce the length of the file. No essential data for
applications is lost with this representation. Additionally, we
have modified the neutron reaction cross sections slightly to
improve agreement with data above 20 MeV.
The evaluation above 20 MeV utilizes MF=6, MT=5 to represent
all reaction data. Production cross sections and emission
spectra are given for neutrons, protons, deuterons, tritons,
alpha particles, gamma rays, and all residual nuclides produced
(A>5) in the reaction chains. To summarize, the ENDF sections
with non-zero data above En = 20 MeV are:
MF=3 MT= 1 Total Cross Section
MT= 2 Elastic Scattering Cross Section
MT= 3 Nonelastic Cross Section
MT= 5 Sum of Binary (n,n') and (n,x) Reactions
MF=4 MT= 2 Elastic Angular Distributions
MF=6 MT= 5 Production Cross Sections and Energy-Angle
Distributions for Emission Neutrons, Protons,
Deuterons, and Alphas; and Angle-Integrated
Spectra for Gamma Rays and Residual Nuclei That
Are Stable Against Particle Emission
The evaluation is based on nuclear model calculations that
have been benchmarked to experimental data, especially for n +
Al27 and p + Al27 reactions [Ch97]. We use the GNASH code system
[Yo92], which utilizes Hauser-Feshbach statistical,
preequilibrium and direct-reaction theories. Spherical optical
model calculations are used to obtain particle transmission
coefficients for the Hauser-Feshbach calculations, as well as
for the elastic neutron angular distributions.
Cross sections and spectra for producing individual residual
nuclei are included for reactions that exceed a cross section of
approximately 1 nb at any energy. The energy-angle-correlations
for all outgoing particles are based on Kalbach systematics
[Ka88].
A model was developed to calculate the energy distributions of
all recoil nuclei in the GNASH calculations [Ch96]. The recoil
energy distributions are represented in the laboratory system in
MT=5, MF=6, and are given as isotropic in the lab system. All
other data in MT=5,MF=6 are given in the center-of-mass system.
This method of representation utilizes the LCT=3 option approved
at the November, 1996, CSEWG meeting..
Preequilibrium corrections were performed in the course of the
GNASH calculations using the exciton model of Kalbach [Ka77,
Ka85], validated by comparison with calculations using Feshbach,
Kerman, Koonin (FKK) theory [Ch93]. Discrete level data from
nuclear data sheets were matched to continuum level densities
using the formulation of Ignatyuk [Ig75] and pairing and shell
parameters from the Cook [Co67] analysis. Neutron and charged-
particle transmission coefficients were obtained from the
optical potentials, as discussed below. Gamma-ray transmission
coefficients were calculated using the Kopecky-Uhl model [Ko90].
The neutron total cross section was evaluated from available
experimental data. From 20 - 40 MeV, the existing ENDF/B-VI.3
total cross section evaluation of Young was adopted; from 40 -
150 MeV, the evaluation was based primarily on Finlay's 1993
measurements [Fi93]. The optical potential of Petler [Pe85],
specially developed for n+Al elastic scattering, was used for
neutrons up to 60 MeV, and above this energy the Madland global
potential [Ma88a] was used. For incident protons, the Petler
neutron potential was modified to account for proton scattering
up to 60 MeV, and again the Madland global potential was used at
higher energies. For deuterons, the potential of Perey and
Perey [Pe63a] was used at all energies, and for tritons the
Becchetti and Greenlees potential [Be71] was adopted. Finally,
the potential of Arthur and Young [Ar80], based on the work of
Lemos [Le72], was used for alpha particles at all energies. DWBA
calculations were performed for inelastic scattering to low-
lying states using the DWUCK code.
While the above optical potentials did describe the
experimental neutron and proton nonelastic cross section data
fairly well, we modified these theoretical predictions slightly
to better agree with the measurements, and renormalized the
transmission coefficients accordingly.
The present evaluation was greatly facilitated by Benck et
al.'s [Be98] measurements of charged-particle producing
reactions on Al for incident neutrons at 63 MeV at Louvain-la-
Neuve, Belgium. Since these data represent the only neutron-
induced emission spectra above 20 MeV, they have been invaluable
for guiding, and testing, our calculations. The proton, triton,
and alpha emission spectra in the Benck et al. measurements are
described very well. However, our deuteron emission calculations
compare poorly with the measurements. Fortunately this has only
a small practical impact since deuteron emission is small
compared to proton emission, and our calculated emission
spectrum approximates the measured deuteron energy deposition
(production cross section times average energy) reasonably well,
which is important for heating calculations. The combination of
equilibrium and preequilibrium reaction mechanisms included in
the GNASH code account for the measured data rather well.
As an independent validation of our GNASH calculations using
the exciton model, we have also performed FKK calculations. This
was done by implementing a multistep reaction theory recently
developed by Koning and Chadwick, which is particularly suited
to the simultaneous calculation of neutron and proton emission.
The FKK theory describes the forward-peaking very well, as do
our exciton model calculations using the phenomenological
Kalbach angular distribution systematics.
As additional validation of the models used in our neutron
evaluation, extensive comparisons were made to higher energy
proton-induced measurements. In particular, the neutron and
charged-particle emission spectra measured at the University of
Maryland (Kalend et al. and Wu et al.) for 90-MeV protons, by
Meier at Los Alamos for 113-MeV protons, and Bertrand and Peelle
for 61-MeV protons are all reproduced reasonably by the present
analysis [Ch97].
Another useful test of our model calculations, particularly
for radionuclide production, can be made by comparing our
theoretical predictions of discrete gamma-ray emission in
Al27(n,xngamma) reactions with the recent LANSCE/WNR data taken
by Vonach, Haight, and collaborators [Vo94] using the white
neutron source. Preliminary comparisons show reasonably good
agreement.
****************************************************************
ENDF/B-VI MOD 2 Revision, August 1996, P. Young (LANL),
V. McLane (NNDC)
File 1: Thermal values added. .
File 3: Corrected interpolation range on first 3 points of MT1
and on first 10 points of MT102.
****************************************************************
ENDF/B-VI MOD 1 Evaluation, November 1994, P.G. Young (LANL)
GENERAL COMMENTS: This evaluation is based on a theoretical
analysis that utilizes Hauser-Feshbach statistical theory, with
corrections for preequilibrium and stripping processes.
Spherical optical model calculations are used to obtain particle
transmission coefficients for the Hauser-Feshbach calculations,
as well as for the elastic neutron angular distributions. Some
data from ENDF/B-VI are retained, in particular, the neutron
total cross section below 20 MeV and the radiative capture cross
section and photon multipicities below about 100 keV.
Cross sections and spectra for individual reactions are
included for reactions that exceed a cross section of
approximately 1 mb at any energy. Multiplicities and emission
energy spectra are given for gamma rays, particles, and recoil
nuclei emitted in each reaction, utilizing File 6 of the ENDF/B-
6 format [Ro91]. Energy-angle-correlated spectra are given for
all outgoing particles.
2200 m/sec cross section resonance integral
------------------------ ------------------
Total 1.58 barns
Elastic 1.35 barns
Capture 0.232 barns 0.134 barns
HAUSER-FESHBACH STATISTICAL THEORY CALCULATIONS: The GNASH
code [Yo92] was used for all Hauser-Feshbach statistical theory
calculations. Preequilibrium corrections were performed in the
course of the GNASH calculations using the exciton model of
Kalbach [Ka77,Ka85]. Discrete level data from nuclear data
sheets were matched to continuum level densities using the
formulation of Ignatyuk [Ig75] and pairing and shell parameters
from the Cook [Co67] analysis. Neutron and charged-particle
transmission coefficients were obtained from the optical
potentials, as discussed below. Gamma-ray transmission
coefficients were calculated using the Kopecky-Uhl model [Ko90].
Calculations were performed for all significant reactions
producing neutrons, protons, deuterons, tritons, alpha
particles, and gamma rays for incident neutrons between 1.0E-11
and 40 MeV. At the highest energies, approximately 30 compound
nuclei had to be included, leading to ~180 reaction paths.
The angular distribution systematics by Kalbach [Ka88] were
used to describe the angular distributions for all continuum
particles.
OPTICAL MODEL POTENTIALS: For incident and exiting neutrons,
the phenomenological optical potential by Petler et al.[Pe85],
based on a microscopic optical model analysis of experimental
data, was utilized at all energies. A modified version of
Perey's potential [Pe63b] was used to calculate transmission
coefficients for protons below 44 MeV, switching to the Madland
potential [Ma88b] at higher energies. The potential by Perey and
Perey [Pe63b] was utilized to calculate deuteron transmission
coefficients for deuterons at all energies. Similarly, a triton
potential by Becchetti and Greenlees [Be71] and an alpha
potential determined by Arthur and Young [Ar80] for n + 56Fe
reactions were used at all energies for those particles.
DIRECT REACTIONS: Energy-dependent cross sections of
inelastic neutrons from Al27(n,n') direct reactions were
calculated using the DWUCK code [Ku70], normalized to values of
the angle-integrated cross sections in ENDF/B-VI at 14 MeV.
ENDF/B-V CARRYOVERS: The following reactions/data were
carried over unchanged from ENDF/B-V:
MF=2, MT=151: Resonance Parameters
Effective scattering radius = 0.32752E-12 cm. (Resonance
parameters not given.)
CALCULATIONAL RESULTS: The MF=3 cross sections and MF=6
energy/angle distributions based completely on calculations are:
MT = 11: (n,2nd) Reaction
MT = 16: (n,2n) Reaction
MT = 17: (n,3n) Reaction
MT = 22: (n,nalpha) Reaction
MT = 24: (n,2nalpha) Reaction
MT = 28: (n,np) Reaction
MT = 29: (n,n2alpha) Reaction
MT = 32: (n,nd) Reaction
MT = 33: (n,nt) Reaction
MT = 41: (n,2np) Reaction
MT = 42: (n,3np) Reaction
MT = 44: (n,n2p) Reaction
MT = 45: (n,npalpha) Reaction
MT = 64-89: (n,n') Discrete Level Reactions
MT = 91: (n,n') Continuum Reaction
MT = 103: (n,p) Reaction (MF=6 only)
MT = 104: (n,d) Reaction
MT = 105: (n,t) Reaction
MT = 107: (n,alpha) Reaction (MF=6 only)
MT = 108: (n,2alpha) Reaction
MT = 111: (n,2p) Reaction
MT = 112: (n,palpha) Reaction
MT = 115: (n,pd) Reaction
MT = 116: (n,pt) Reaction
MT = 117: (n,dalpha) Reaction
MT = 649: (n,p) Continuum Reaction
MT = 650-669: (n,d) Discrete Level Reactions
MT = 699: (n,d) Continuum Reaction
MT = 700-710: (n,t) Discrete Level Reactions
MT = 749: (n,t) Continuum Reaction
MT = 849: (n,alpha) Continuum Reaction
Kalbach systematics [Ka88] are used to specify all continuum
particle angular distributions. All continuum photon angular
distributions are assumed isotropic.
Additionally, the radioactive nuclei formation data in MF = 8
and 9 were obtained directly from the GNASH calculations.
OTHER REACTIONS: The following reactions are based on
combinations of experimental data and theoretical calculations
or other techniques:
MF=3,MT=1: Total Cross Section.
Below 20 MeV, carried over from ENDF/B-V. At higher energies
based on data of Pe72 and optical model calculation.
MF=3,MT=2: Elastic Cross Section.
Obtained by subtracting sum of nonelastic cross sections from
the total. Mainly results from the optical model calculations
above 14 MeV. At lower energies the nonelastic cross sections
are a combination of experimental data (ENDF/B-V evaluations)
and the theoretical calculations.
MF=3,MT=4: Inelastic Cross Section.
Summation of MT=51-91.
MF=3,MT=51-63: Inelastic Cross Section to Discrete States.
Combination of experimental data below 14 MeV [especially (n,n')
data of Ki70 and (n,xgamma) data of Or71, Di71, and Di73] and
calculated excitation functions, with a rough match to the
ENDF/B-V evaluation near 14 MeV.
MF=3, MT=102: (n,gamma) Cross Section.
Below 1 keV, ENDF/B-V was adopted. At higher energies,
calculations from GNASH code used, including a semidirect model.
MF=3,MT=103: (n,p) Cross Section.
Taken directly from the International Reactor Dosimetry File
IRDF-90 of the IAEA, which was obtained at the Institut fuer
Radiumforschung und Kernphysik (IRK) in Vienna [Wa90]. At
higher energies, calculated excitation function were used,
normalized to the IRK data at 20 MeV.
MF=3,MT=107: (n,alpha) Cross Section.
Taken directly from the International Reactor Dosimetry File
IRDF-90 of the IAEA, which was obtained at the Institut fuer
Radiumforschung und Kernphysik (IRK) in Vienna [Wa90]. At
higher energies, calculated excitation function were used,
normalized to the IRK data at 20 MeV.
MF=4, MT=2: Elastic Angular Distributions.
ENDF/B-V adopted below En = 6 MeV. At higher energy optical
model calculations used (see above). Tabulated distributions
given in the center-of-mass system.
MF=6, MT=51-89: Inelastic Level Neutron & Photon Distributions.
For MT=51-62, neutron angular distributions are combination of
experimental data and calculated shapes below 14 MeV and are
represented by Legendre expansions in the CM system. At higher
energies, calculated shapes are used. For MT=63-89, calculated
angular distributions are used at all energies. Photon
multiplicities based on experimental branching ratios and GNASH
calculations. Photon angular distributions assumed isotropic.
MF=12, MT=102: Radiative Capture Photon Multiplicities.
Below 1 keV, ENDF/B-V adopted. At higher energies, based on
GNASH calculations.
MF=15, MT=102: Radiative Capture Photon Energy Distributions.
Below 1 keV, ENDF/B-V adopted. At higher energies, based on
GNASH calculations.
*****************************************************************
REFERENCES
[Ar80] E.D. Arthur and P.G. Young, Proc. Sym. on Neutron Cross
Sections from 10 to 50 MeV, 12-14 May 1980, Brookhaven National
Laboratory [Eds. M.R. Bhat and S. Pearlstein], report
BNL-NCS-51245 (1980) p.731
[Be69] F.D. Becchetti, Jr., and G.W. Greenlees, Phys.Rev. 182,
1190 (1969)
[Be71] F.D. Becchetti, Jr., and G.W. Greenlees, Polarization
Phenomena in Nuclear Reactions, Proc. Conf. [Ed: H.H.Barschall
and W.Haeberli] (The University of Wisconsin Press, 1971) p.682
[Be92] O. Bersillon, "SCAT2 - A Spherical Optical Model Code,"
in Proc. ICTP Workshop on Computation and Analysis of Nuclear
Data Relevant to Nuclear Energy and Safety, 10 February-13
March, 1992, Trieste, Italy, to be published in World Scientific
Press, and Progress Report of the Nuclear Physics Division,
Bruyeres-le-Chatel 1977, CEA-N-2037 (1978) p.111
[Be98] S. Benck, I. Slypen, J.P. Meulders, et al., Phys.Rev.C
58, 1558 (1998); S. Benck, Ph.D. thesis, Louvain-la-Neuve,
Belgium (1997)
[Ch93] M.B. Chadwick and P.G. Young, Phys.Rev. C 47, 2255 (1993)
[Ch96] M.B. Chadwick, P.G. Young, R.E. MacFarlane, and A.J.
Koning, "High-Energy Nuclear Data Libraries for Accelerator-
Driven Technologies: Calculational Method for Heavy Recoils,"
Proc. of 2nd Int. Conf. on Accelerator Driven Transmutation
Technology and Applications, Kalmar, Sweden, 3-7 June 1996.
[Ch97] M.B. Chadwick and P.G. Young, "GNASH Calculations of
n,p + 27Al and Benchmarking of Results" in APT PROGRESS REPORT:
1 January - 1 February 1997, internal Los Alamos National
Laboratory memo T-2-97/MS-52, 6 Feb.1997 from R.E. MacFarlane to
L. Waters.
[Ch99] M.B. Chadwick, P.G. Young, G.M. Hale, et al., Los Alamos
National Laboratory report, LA-UR-99-1222 (1999)
[Co67] J.L. Cook, H. Ferguson, and A.R. De L Musgrove, Aust.J.
Phys. 20, 477 (1967)
[Di71] J.K. Dickens et al., report ORNL-TM-3284 (1971)
[Di73] J.K. Dickens et al., report ORNL-TM-4232 (1973)
[Fi93] R.W. Finlay, W.P. Abfalterer, G. Fink, et al., Phys.Rev.
C 47, 237 (1993)
[Ig75] A.V. Ignatyuk, G.N. Smirenkin, and A.S. Tishin, Sov.J.
Nucl.Phys. 21, 255 (1975); translation of Yad.Fiz. 21, 485
(1975)
[Ka77] C. Kalbach, Z.Phys.A 283, 401 (1977)
[Ka85] C. Kalbach, Los Alamos National Laboratory report
LA-10248-MS (1985)
[Ka88] C. Kalbach, Phys.Rev.C 23, 112 (1981)
[Ki70] W.E. Kinney and F.G. Perey, report ORNL-4516 (1970)
[Ko90] J. Kopecky and M. Uhl, Phys.Rev. C 41, 1941 (1990)
[Ku70] P.D. Kunz, "DWUCK - A Distorted Wave Born Approximation
Program," (1970) unpublished
[Le72] O.F. Lemos, "Diffusion Elastique de Particules Alpha
de 21 a 29.6 MeV sur des Noyaux de la Region Ti-Zn," Orsay
report, Series A, No. 136 (1976)
[Ma88a] D.G. Madland, Proc. OECD/NEANDC Specialist's Mtg. on
Preequilibrium Nuclear Reactions, Semmering, Austria, Feb.
1988, report NEANDC-245 'U' (1988) p.103
[Ma88b] D.G. Madland, International Atomic Energy Agency report
IAEA-TECDOC-483 (1988) p.80
[Or71] V.J. Orphan and C.G. Hoot, Gulf General Atomic report
GULF-RT-A10743 (1971)
[Pe63a] C.M. Perey and F.G. Perey, Phys.Rev. 132, 755 (1963)
[Pe63b] F.G. Perey, Phys.Rev. 131, 745 (1963)
[Pe72] F.G. Perey, et al., report ORNL-4823 (1972)
[Pe85] J.S. Petler, M.S. Islam, and R.W. Finlay, Phys.Rev.C 32,
673 (1985)
[Ro91] P. Rose, Brookhaven National Laboratory informal report
BNL-NCS-44945 [ENDF-102, Rev. 10/91] (1991)
[Vo94] H. Vonach, A. Pavlik, M.B. Chadwick, et al., Phys.Rev.C
50, 1952 (1994)
[Wa90] M. Wagner, H. Vonach, A. Pavlik, et al., Physics Data
13-5 (Fachinformationszentrum Karlsruhe, 1990)
[Yo92] P.G. Young, E.D. Arthur, and M.B. Chadwick, report
LA-12343-MS (1992)
[Yo94] P.G. Young, "Evaluation of n + 27Al Cross Sections for
the Energy Range 10-5 eV to 40 MeV," ENDF/B-VI Release 3
evaluation, Nov., 1994
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