Nuclear Theory and Applications - Progress Rpt [Jan 89 - Apr 90]

144 Pages·1990·9.308 MB·English

I_A-]1972-PR
l_rnyr,css Rcp(,'t
LIC-O00and LIC-413
Issued: Decont_cr13L3C0
LA--li 972-PR
DI_9.l OO49O2
Nuclear Theory and Applications
Progress Report
January 1, 1989-April 1, 1990
Compiled by
D. D. Strottman
A. D. Mutschlecner
MASTER
'" _ - _....... LosAlamosNationalLaboratory
....,.,-,....M;;:/i'ii;,!,!ii: LosAlamos,NewMexico 87545
CONTENTS
ABSTRACT ............................................................................................. i
I. DATA EVALUATION AND 1.2BRARIES ................................................ 1
A. Data Evaluations for Version VI ofENDF/B-VI .......................................... 1
B. Analysis and Evaluation ofn + 14NNuclear Reactions for ENDF/B-VI ............... 2
C. R-Matrix Analysis of the 170 System ....................................................... 7
D. Theoretical Analyses ofNeutron-Induced Reactions on Acthfides for ENDF/B-VI:
235U, 238U, 237Np, and 239pu.............................................................. 9
E. TranspolarData Libraries for Incident Proton and Neutron Energies to 100 MeV ..... 17
F. References-Section I.......................................................................... 18
II. DATA PROCESSING ........................................................................ 21
A. NJOY 89 ....................................................................................... 21
1 NJOY .................................................................................. 21
2 RECONR .............................................................................. 21
3 BROADR .............................................................................. 24
4 UNRESR .............................................................................. 24
5 HEATR ................................................................................ 25
6 THERMR ............................................................................. 27
7 GROUPR ............................................................................. 29
8 GAMINR .............................................................................. 35
9 ERRORR and COVR................................................................ 35
10. MODER ............................................................................... 35
11. DTFR .................................................................................. 35
12. CCCCR ................................................................................ 35
13. MATXSR ............................................................................. 35
14. ACER .................................................................................. 36
15. POWR ................................................................................. 37
16. PLOTR ................................................................................ 37
B. MENDLIB ..................................................................................... 39
C. References-Section II......................................................................... 40
III. NUCLEAR APPLICATIONS ............................................................... 42
A. Transmutation ofDefense High Level Nuclear Wastes Using High Current
Accelerators ..................................................................................... 42
B. Application of Fission-Product, Actinide, and Activation Data.......................... 44
V
C. Data trodCode Development forTransmutation C_dculations............................ 45
D. Ion Induced Thick-T,'u'get Nuclide Production and Radiation Sources ................. 46
E. References-Section III ........................................................................ 47
IV. REACTIONS .................................................................................. 49
A. DoubleoDifferential Cross-Section CaJ,'flations Based on aMonte-Carlo Formulation
of the Multistage Preequilibrium Model .................................................... 49
B. Quasi-Free Scattering (QFS) in the Preequilibrium Region .............................. 50
C. Phenomenology ofQuasi-Free Scattering .................................................. 52
D. 98-MEV Deuterons Incident ota 27AI and 238U ............................................ 52
E. Correction for Truncation in Coupled-Channels Optical Potentials ..................... 55
F. haitial Deuteron-Nucleus Global Optical-Model Potential for NPB Target
Discrimination Calculations .................................................................. 56
G. Dirac Optical Potentials for Nucleon Scattering by 208pb atIntermediate Energies...56
H. Deuteron-Nucleus Optical Potential Analysis at Medium Energies ..................... 59
I. Prediction of Intemaediate-Energy Neutron Scattering Observables from a Dirac
OpticalPotential ............................................................................... 60
J. Electrodisintegration ofthe Deuteron ....................................................... 61
K. Dynamics ofPion Double-Charge-Exchange Reactions .................................. 63
L. Two-Nucleon Correlations in Pion Double Charge Exchange ........................... 65
M. Microscopic Field Theoretical Treatment of Ultrarelativistic Nucleus-Nucleus
Collisions ....................................................................................... 67
N. Pion-Nucleus Elastic Scattering in theMicroscopic Local Delta-Hole Model .......... 70
O. Pion-Nucleus Single-Charge Exchange Above the Resonance .......................... 72
P. Pion Distributions from the Fluid Dynamical Model ofUltra-relativistic Heavy Ion
Collisions ....................................................................................... 74
Q. Equilibration in Relativistic Nuclear Collisions:
Two-Fluid Hydrodynamics vs Experiment ................................................ 76
R. Hadronization from Supercooled Baryon-rich Quark Gluon Plasma ................... 77
S. References-Section IV ........................................................................ 80
V. FISSION ....................................................................................... 83
A. Heavy-Element Fission Barriers ............................................................. 83
B. Heavy,Element Fission Half-Lives ......................................................... 84
C. Theory of Neutron Emission in Fission .................................................... 86
D. Fission Neutron Spectra for 240pu, 238Pu, and 242Pu ................................... 86
E. An Improved Model for the Calculation ofPrompt Fission Neutron and Gamma-
Ray Data........................................................................................ 86
vt
F. Calculation ofMedium Energy Nucleon-Nucleus Fission Cross Sections ............. 92
G. Activation, Actinide, madFission-Product Yields and Decay Data ...................... 96
1. Decay Data (Average Energies and Spectra) ...................................... 96
2. Delayed Neutrons ...... .............................................................. 103
3. Yields .................................................................................. 105
H. References-Section V ............................... ,......................................... 110
VI. NUCLEAR STRUCTURE .................................................................. 114
A. Nuclear Level Density Sensitivity Studies .................................................. 114
B. P-Wave Pion Scattering in the Los Alamos Soliton Model ............................... 117
C. Maximum Velocity inthe Los Alamos Soliton Model and in Other Nonrelativistic
Quantmn Field Theories ...................................................................... 118
D. Canonical Transformation Method for Static-Source Meson Hamiltonians ............ 119
E. The Shell Model ofthe Nucleon -The Nucleon as a Few-.Body System ............... 120
F. [3-Delayed Proton Decay ............ .......................................................... 120
G. New Developments inthe Calculation of [_-StrengthFunctions ......................... 12l
H. _-Decay Properties ofA ---80 Nuclei and Implications for Astrophysics .............. 125
I. Acthaide Nuclear-Structure Properties and Implications for Astrophysics .............. 125
J. Relativistic Point Coupling Model for theDescription of Nuclear Ground State
Properties ......................................... .............................................. 127
K. Emission and Detection of Hadronic Axions from SN87A ..... ,........................ 127
L. The Soft Giant Dipole Mode of llLi ........................................................ 128
M. Nuclear Structure Corrections to Estimates of the Spin-Dependent Wimp-Nucleus
Cross Section .................................................................................. 128
N. Spin-Tensor Analysis of Realistic Shell Model Interactions ............................. 130
O. Two-Photon Decay of the First Excited O+State in 160 ................................. 132
P. References-Section VI ........................................................................ 133
VII. OTHER THEORY ............................................................................ 134
A. A Neural Model for Gamma-Ray Spectrum Recognition ................................. 134
B. Cold Fusion Topics ........................................................................... 135
C. Cold Fusion Theory ........................................................................... 136
D. Particle Filtration .............................................................................. 137
E. Heisenberg Antiferrom agnet ................................................................. 137
F. Nuclear-Model Parameter Searches and Covariance Capability ......................... 138
G. References-Section VII ....................................................................... 139
vii
NUCLEAR THEORY AND APPLICATIONS
PROGRESS REPORT
January 1, 1989-April 1,1990
Compiled by
D. D. Strottman and A. D. Mutschlecner
¢
ABSTRACT
This progress repor_ describes the activities of the Los
Alamos Nuclear Theory and Applications Group for January 1,
1989 through April 1, 1990. The topical content is summarized in
the Contents.
I. DATA EVALUATION AND LIBRARIES
A. Data Evaluations for Version VI of ENDF/B-VI (P. G. Young, D. Dodder, G. M. Hale,
and R. E. MacFarlane)
Evaluations of neutron-induced data for the upcoming issue of Version VI of ENDF/B are
complete or in progress for lH, 3He, 6Li, 7Li, 10B, liB, 14N, 15N, 160, 151Eu, 153Eu, 165Ho,
197Au, 235U,238U, 237Np, and 239pu. Additionally, proton-induced evaluated data files for lH
and 3He targets have been accepted for ENDF/B-VI. Over the past year, evaluations for ali these
materials except 14N and 160 were provided tothe National Nuclear Data Center at Brookhaven for
Version VI. The analyses for 14Nand 160 are still in progress and are described in Secs. B and C.
The evaluations cover the incident nucleon energy range up to 20 MeV or higher and, hamost
cases, new ENDF/B formats that permit precise specification ofenergy-angle correlations in emis-
sion spectra areutilized, in addition to incorporating up-to-date assessments of the available exper-
imental data, each evaluation includes results of theoretical analyses to complement the experimen-
tal information. In the case of light elements, R-matrix analyses have been performed; for heavier
materials, Hauser-Feshbach statistical calculations with supporting coupled-channel or spherical
optical model, preequilibrium, direct reaction, and fission theory (for actinides) analyses are com-
plete. A summary ofthe theoretical analyses for the actinide evaluations isgiven in Section B.
B. Analysis madEvaluation of n + 14N Nuclear Reactions for EN D_B/_B_=V(P_.IG. Young)
An evaluation of n + 14N nuclear data was begun in 1989 arid will be completed for the
first issue of ENDF/B-VI in 1990. The evaluation is divided into two p_urts: (1) a coupled-chan-
i_el, R-matrix analysis incorporating ali available data (including polarization and p + 14C data) is
being petTormed tlp to the threshold for inelastic scattering (En = 2.5 MEV), and (2) an assessnlent
and evaluation of all experimental data are being carried out for the incident neutron energy range
En = 2 - 20 MeV. At present, the R-matrix analysis is still in progress, bt,t the experimental data
evaluation is essentially complete and is summarized below.
The previous evaluation of neutron-induced reactions with 14Nwas completc'd in the early
1970's 1and was part of an intensive effort by the Defense Nuclear Agency to improve calcula-
tional capabilities for transporting neutrons and T-rays through the atmosphere. The results of that
analy:3is have been carried over basically unchanged in ENDF/B libraries since that time. 2 The
availability of new and improved experimental data and theoretical techniques, together with the
identification of discrepancies between measurements and calculations involving the transport of
neutrons through large distances in air, has motivated the present effort. For orientation, graphs
of the total, elastic, and nonelastic scattering cross sections are given in Fig. I-1. The importance
of adequately describing properties of the low-energy resonances, particularly as regards the
transport of lower energy neutrons, is clear from the figure. While our R-matrix analysis will
represent the resonances to 2 MeV, it is in]portant to note that pronounced structure continues to
neutron energies of 9 MeV or higher, with a major feature of the data (from the point of view of
neutron transport) being the neutron total cross section minimum near 5MeV.
Major new experiments completed since 1973 include measurements by Chardine etal.3of
neutron elastic and inelastic scattering angular distributions to the lowest five excited states of 14N
for incident neutron energies between 7.7 and 13.5 MeV, mad elastic scattering measurements by
Templon et al.4at three energies between 11 and 17MeV, by Perey and Dickens 5between 4.3 and
8.6 MeV, by Baba et al.6 at 14.2 MeV, and by Petler et al.7at 20 and 25 MeV. Important new in-
formation on neutron inelastic scattering is provided by the measurements of Nelson et al., 8
Auchampaugh and Wender* and Rogers et al.9up to En = 20 MeV, as well as the exteL_sive
double-differential neutron emission measurements by Baba et al.6and Takahashi et al.10for En -=
14 MeV. A comprehensive new measurement of 14N(n,p) and 14N(n,ct) cross sections to discrete
states by Morgan 11up to En = 14 MeV is useful for the experimental data evaluation as well as the
R-matrix studies. Unfortunately, the only major new total cross section measurement, 12covering
the important energy range En = 0.97 to 5.3 MeV, is in substantial disagreement (.--14%) with
older, precision measurements and was not included in our evaluation.
*GeorgeAuchampaugh,andStevenWender(LosAlamosNationalLaboratory)suppliedthisinformation in 1986.
_--'_al_ I I I i......I I i i I "l ...J..,... "'( I I' i t
A AA A _;
m7 _ J NONELASTIC _-3
__'_ _ ,,,I -I i,i l_l _ ...i _ I._l_t, -
a*lO-' i0° lfr
NEUTRON ENERGY(MEV)
Fig. I-1. Total, elastic, and nonelastic cross sections for n + 14Ninteractions.
The new experimental measurements resulted in considerable modification of some of the
evaluated data. Comparisons ofthe newly evaluated 14N(n,n') cross sections to the f'trst 3excited
states with the previous ENDF/B evaluations are given in the upper halves of Figs. 1-2through I-
4, also including the available experimental data. Gamma-ray production cross sections for
emission ofprominent ),-rays from these same states are shown in the lower halves of Figs. 1-2- I-
4. To further illustrate the extent of some of the changes, new and old inelastic (Ex =2.31 MeV)
angular distributions are compared at selected energies in Figs. 1-5and I-6. Finally, a comparison
of the new and previous evaluated elastic scattering cross section between 6 and 20 MeV is given
in Fig. 1-7. Note that the cross section has increased by some 9% at En= 14MeV.
The results ofthe R-matrix analyl_isand experimental data evaluation summarized here will
be included in the first issue of ENDF/B-VI,
I I I I I I 1
e/o _ .. "_.._.
ENI)F/B- V .....
Cc_) _ ¥ CHARDINE, 1986 "'- 2.313-MEV state
m ,_, I I " I ENDII'yB-.V.I.a. I I .............t --... laN(n,n')
0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0
I I I I 1 I I
Z -
_._ 7_" d_ _' I .......... E_,LN.,AD/._F'--/.B xr ] "_"&'t'4r_"_'* k -I
W_ _,' _ ENDF/B-VIa T
I_. ,,t_ " A NELSON, 1990
r.D + ROGERS, 1974 __
_:_O o AUCHAMPAUGH, 1986 __
r..)7 x NELLIS, 1971 ET= 2.313 MeV
50 i _" . iOi DBEICYKSETNESR,, 11996699 _:-.7 laN(n,n,y)
0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0
NEUTRON ENERGY (MEV)
Fig.I-2. Inelastniecutronand?-raycrosssectionfsrom14N(n,n'r)eactiontsothefirsetxcited
stat(eEx= 2.313MeV) of14N.Thenew evaluatio(nsolicdurve)iscomparedwiththeprevious
ENDP/B-V evaluati(odnashecdurvea)ndwiththeavailabelxeperimentdaalta.
1 I I I I I I
•
Z
o _-
_
F-aI0,.l .......
_ ,,-,-I": "__'- ...... 14N(n,n,)
C/_ :/I _ ENDF/B-VIa : 3.948-MeVstate
0 .; + CHARDINE, 1986
i2_ a PEREY, 1974
4.0 6.0 8.0 10.0 12.0 14.0 16.0 1B.O 20.0
I I I I I I I
z ! _ .
'0 _sI _ ENDF/B-VIa u_ _4 _ W'_
_l T g
,,-,i _;i A NELSON, 1990 /
5_0 "--ii o BEYSTER, 1969 / _ ' I 14N(n,n'?)
0 -!1 + ROGERS,, "1974 t __
fr2.._)_ -ii,, ×ii NDEICLKLIESN,S",19179169 / __ Ey= 1.635 MeV
i._ _ ,"i I I I I I I I
4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
NEUTRON ENERGY (MEV)
Fig. I-3. Inelastic neutron and y-ray cross sections from 14N(n,n') rcactions to the second
excited state (Ex = 3.948 MEV:)of 14N. The new evaluation (solid curve) is compared with the
previous ENDF/B-V evaluation (dashed curve) and with the available experimental data.
I I I I I I I
Z_, + +4 +
cn - ENDF/B-V " 4.915-MEV state
59 - ENDF/B-VIa -
O - + CHARDINE, 1986-
_mrOTD( -- i i a PEREY, 1974 14N(n'n')
4.0 8.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
-
C5QO "' + ..... ENDF/B- V 14N(n,n'Y )
CO - ENDF/B-VIa
O + ROGERS, 1974 ET= 4.915 MeV
- i DICKENS, 1969
r.-)7o ] o BEYSTER, 1969
LO 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
NEUTRON ENERGY (MEV)
Fig. I-4. Inelastic neutron and y-ray cross sections from 14N(n,n') reactions to the third excited
state (Ex = 4.9i5 MeV) of 14N. The new evaluation (solid cwve) is compared with the previous
ENDF/B-V evaluation (dashed curve) and to the available expenmemal data.
ccd __ ENDF/B-VIa
..... ENDWB-V
v BAUER, 1967
a CHARDINE, 1986
+ PEREY, 1974
"tD "_
....
":%
50
_.92 !'"+":"".--7.
•., MeV.................... Fig. I-5. Measured and evaluated n +
I_ -,......... .,**°
lgN elastic scattering angular
, , , , , , , distributions. The solid curves are
Loo o.75 0.50 o.z5 0.00 -o.z5 -o.ao -o.75 -1.00 the present evaluation and the dashed
COS THETA (cm) curves are ENDF/B-V.
ENDF//B-VIa
ENDF/B-V
13.50 MeV _" CttARDINE, 19136
%
..........._.._.._.,____ ....
"'",,, s'
.°. "'., ........ ..°,.. ........... ....,..,,'
'_"O:
2; 12,4.0 MeV
'o ""', , *
"". .................. oy'
u_ "°'• ................................ ,'°'°
Fig. I-6. Measured and evaluated
.65MeV inelastic scattering angular distribu-
'__J .-_..._, ,,," tions for tile first excited state of 14N
are the present evaluation and the
r"o-'1""""" ............."'"_"<2"_<'" adtasEhxed= c2u.3rv1e3s MareeV.ENTDhFe/Bs-oVli.d curves
" 1.ooo'.750:50 olz5 oloo-o'.z5-&o-0'.75-1.oo
COSTHETA(eta)
0
_'I I I I I , I I I
' 4
r/?
o
c_
O
°- I I t I I I t
0.00 1t.25 I2.50 13.75 15,00 16,25 17.50 10,75 E0.00
"4 [ I I 1 I I I I
O_etl - I "',, ,"",
co 2_22_-
bq
©
f#,
r..)
. d_ I I I I I i I
6,0 6.5 7.0 7,5 8.0 8.5 9.0 9.5 10,0
NEUTRON ENERGY (MEV)
Fig. I-7. Neutron elastic scattering cross section for 14N between 6 and 20 MeV. The solid
curve is the present evaluation and the dashed curve is from ENDF/B-V.