55 Matching Results

Search Results

Advanced search parameters have been applied.

Note on the elastic-scattering of few-MeV neutrons from elemental calcium

Description: Neutron differential-elastic-scattering cross sections of elemental calcium are measured from < 1.5 to 4.0 MeV at intervals of approx. = 50 to 100 keV. Scattering angles are distributed between 20 and 160/sup 0/. Incident-neutron energy resolutions are approximately 50 to 100 keV. The experimental results are compared with values given in ENDF/B-V and are examined in the context of shielding applications. An optical potential is deduced from the measured values and its possible implications are discussed.
Date: March 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Fast-neutron scattering cross sections of elemental silver

Description: Differential neutron elastic- and inelastic-scattering cross sections of elemental silver are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV and at 10 to 20 scattering angles distributed between 20 and 160/sup 0/. Inelastically-scattered neutron groups are observed corresponding to the excitation of levels at; 328 +- 13, 419 +- 50, 748 +- 25, 908 +- 26, 1150 +- 38, 1286 +- 25, 1507 +- 20, 1623 +- 30, 1835 +- 20 and 1944 +- 26 keV. The experimental results are used to derive an optical-statistical model that provides a good description of the observed cross sections. The measured values are compared with corresponding quantities given in ENDF/B-V.
Date: May 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Neutron inelastic-scattering cross sections of /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu and /sup 240/Pu. [LMFBR]

Description: Differential-neutron-emission cross sections of /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu and /sup 240/Pu are measured between approx. = 1.0 and 3.5 MeV with the angle and magnitude detail needed to provide angle-integrated emission cross sections to approx. < 3% accuracies. Emitted-neutron resolutions are quantitatively defined and vary from approx. = 0.1 to 0.35 MeV. The experimental results are corrected for fisson-neutron contributions to obtain pseudo-elastic-neutron-scattering cross sections which, together with the neutron total cross sections, define the non-elastic cross sections to within well specified energy resolutions. These results imply inelastic-neutron-scattering cross sections which are compared with comparable quantities derived from ENDF/B-V. Good general agreement is noted for /sup 232/Th, /sup 233/U, /sup 235/U and /sup 238/U inelastic-scattering values, poor agreement is observed for /sup 240/Pu, and a serious discrepancy exists in the case of /sup 239/Pu.
Date: January 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Covariances for neutron cross sections calculated using a regional model based on local-model fits to experimental data

Description: We suggest a procedure for estimating uncertainties in neutron cross sections calculated with a nuclear model descriptive of a specific mass region. It applies standard error propagation techniques, using a model-parameter covariance matrix. Generally, available codes do not generate covariance information in conjunction with their fitting algorithms. Therefore, we resort to estimating a relative covariance matrix a posteriori from a statistical examination of the scatter of elemental parameter values about the regional representation. We numerically demonstrate our method by considering an optical-statistical model analysis of a body of total and elastic scattering data for the light fission-fragment mass region. In this example, strong uncertainty correlations emerge and they conspire to reduce estimated errors to some 50% of those obtained from a naive uncorrelated summation in quadrature. 37 references.
Date: November 1, 1983
Creator: Smith, D.L. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Fast-neutron scattering from elemental cadmium

Description: Neutron differential-elastic-scattering cross sections of elemental cadmium are measured from approx. = 1.5 to 4.0 MeV at incident-neutron energy intervals of 50 to 200 keV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Concurrently, lumped-level neutron inelastic-excitation cross sections are measured. The experimental results are used to deduce parameters of an optical-statistical model that is descriptive of the observables and are compared with corresponding quantities given in ENDF/B-V.
Date: July 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Scattering of fast neutrons from elemental molybdenum

Description: Differential broad-resolution neutron-scattering cross sections of elemental molybdenum were measured at 10 to 20 scattering angles distributed between 20 and 160 degrees and at incident-neutron energy intervals of approx. = 50 to 200 keV from 1.5 to 4.0 MeV. Elastically-scattered neutrons were fully resolved from inelastic events. Lumped-level inelastic-neutron-scattering cross sections were determined corresponding to observed excitation energies of; 789 +- 23, 195 +- 23, 1500 +- 34, 1617 +- 12, 1787, 1874, 1991, 2063 +- 24, 2296, 2569 and 2802 keV. An optical-statistical model was deduced from the measured elastic-scattering results. The experimental values were compared with the respective quantities given in ENDF/B-V.
Date: November 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Fast-neutron scattering cross sections of elemental zirconium

Description: Differential neturon-elastic-scattering cross sections of elemental zirconium are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV. Inelastic-neutron-scattering cross sections corresponding to the excitation of levels at observed energies of: 914 +- 25, 1476 +- 37, 1787 +- 23, 2101 +- 26, 2221 +- 17, 2363 +- 14, 2791 +- 15 and 3101 +- 25 keV are determined. The experimental results are interpreted in terms of the optical-statistical model and are compared with corresponding quantities given in ENDF/B-V.
Date: December 1, 1982
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Angular-distribution neutron-emission spectra of niobium following bombardment by fast neutrons

Description: Neutron-emission spectra at ten angles between 20 and 160/sup 0/ and incident neutron energies of 5.9, 7.1 and 8.4 MeV were measured relative to the neutron field emitted after spontaneous fission of /sup 252/Cf. The angular distribution of inelastically scattered neutrons appears to be essentially isotropic where it can be separated from the dominant elastic scattering peak. Above an excitation energy of 4 MeV the spectra are well described by a Maxwellian temperature distribution.
Date: January 1, 1985
Creator: Guenther, P.T. & Smith, A.B.
Partner: UNT Libraries Government Documents Department

Fast-neutron total and scattering cross sections of elemental palladium

Description: Neutron total cross sections of palladium are measured from approx. = 0.6 to 4.5 MeV with resolutions of approx. = 30 to 70 keV at intervals of less than or equal to 50 keV. Differential neutron elastic- and inelastic-scattering cross sections are measured from 1.4 to 3.85 MeV at intervals of 50 to 100 keV and at 10 to 20 scattering angles distributed between approx. = 20 and 160/sup 0/. The experimental results are compared with respective quantities given in ENDF/B-V and used to deduce an optical potential that provides a good description of the measured values.
Date: June 1, 1982
Creator: Smith, A.B.; Guenther, P.T. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department

Nonelastic-scattering cross sections of elemental nickel. [1. 3 to 4. 5 MeV]

Description: Neutron total cross sections of elemental nickel were measured from 1.3 to 4.5 MeV, at intervals of approx. 50 keV, with resolutions of 30 to 50 keV and to accuracies of 1 to 2.5%. Neutron differential-elastic-scattering cross sections were measured from 1.45 to 3.8 MeV, at intervals and with resolutions comparable to those of the total cross sections, and to accuracies of 3 to 5%. The nonelastic-scattering cross section is derived from the measured values to accuracies of greater than or equal to 6%. The experimental results are compared with previously reported values as represented by ENDF/B-V, and areas of consistency and discrepancy, noted. The measured results are shown to be in good agreement with the predictions of a model previously reported by the authors. 4 figures, 1 table.
Date: June 1, 1980
Creator: Smith, A.B.; Guenther, P.T. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department

Fast-neutron interactions with /sup 182/W, /sup 184/W and /sup 186/W

Description: Neutron total cross sections of /sup 182/W, /sup 184/W and /sup 186/W are measured from approx. = 0.3 to 5.0 MeV at intervals of less than or equal to 50 keV to accuracies of 1 to 3%. Differential neutron elastic- and inelastic-scattering cross sections of the same three isotopes are measured at scattering angles in the range 20 to 160/sup 0/ and at incident-neutron energy intervals of approx. = 100 keV from 1.5 to 4.0 MeV. Approximately thirty scattered-neutron groups are observed for each of the isotopes. Prominent of these are excitations attributed to collective rotational and vibrational bands. The experimental results are interpreted in terms of optical-statistical and coupled-channels models with particular attention to the direct excitation of ground-state-rotational and ..beta..- and ..gamma..-vibrational bands. The strengths of the direct interactions and the magnitudes of the collective deformations are inferred from the interpretations and compared with similar values previously reported elsewhere. The experimental results are used to deduce experimentally-based evaluated data sets for /sup 182/W, /sup 184/W and /sup 186/W over the energy range 0.1 - approx. = 5.0 MeV.
Date: June 1, 1981
Creator: Guenther, P.T.; Smith, A.B. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department

Fast-neutron-spectrum measurements for the thick-target /sup 9/Be(d,n)/sup 10/B reaction at E/sub d/ = 7 MeV

Description: Spectra of neutrons with energies greater than or equal to 800 keV which are emitted from a metallic beryllium target that is thick enough to completely stop 7-MeV incident deuterons are measured using organic scintillators and the pulse-beam time-of-flight method. Data are acquired for twenty different emission angles in the laboratory over the range 0 to 155 degrees. The resulting information on the energy-angle detail of neutron emission is then employed in calculations which are performed in order to examine certain effects of the anisotropic neutron production on typical measurements of integral fast-neutron reaction cross sections. 28 refs.
Date: April 1, 1985
Creator: Smith, D.L.; Meadows, J.W. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Energy dependence of the optical model of neutron scattering from niobium

Description: Neutron differential-elastic-scattering cross sections of niobium were measured from 1.5 to 10.0 MeV at intervals of less than or equal to200 keV below 4.0 MeV, and of approx. =500 keV from 4.0 to 10.0 MeV. Ten to more than fifty differential-cross-section values were determined at each incident energy, distributed over the angular range approx. =20 to 160/sup 0/. The observed values were interpreted in the context of the spherical optical-statistical model. It was found that the volume integral of the real potential decreased with energy whereas the integral of the imaginary part increased. The energy dependence in both cases was consistent with a linear variation. There is a dispersion relationship between the real and imaginary potentials, and when this was used, in conjunction with the experimental imaginary potential, it was possible to predict the observed energy dependence of the real potential to a good degree of accuracy, thus supporting the consistency of the data and its analysis. The real-potential well depths needed to give the correct binding energies of the 2d/sub 5/2/, 3s/sub 1/2/, 2d/sub 3/2/ and 1g/sub 7/2/ particle states and of the 1g/sub 9/2/ hole state are in reasonable agreement with those given by a linear extrapolation of the scattering potential. However, the well depths needed to give the observed binding of the 2p/sub 3/2/, 1f/sub 5/2/ and 2p/sub 1/2/ hole states are about 10% less than the extrapolated values. 40 refs., 5 figs.
Date: May 1, 1985
Creator: Smith, A.B.; Guenther, P.T. & Lawson, R.D.
Partner: UNT Libraries Government Documents Department

Some remarks on the neutron elastic- and enelastic-scattering cross sections of palladium

Description: The cross sections for the elastic-scattering of 5.9, 7.1 and 8.0 MeV neutrons from elemental palladium were measured at forty scattering angles distributed between approx.15/degree/ and 160/degree/. The inelastic-scattering cross sections for the excitation of palladium levels at energies of 260 keV to 560 keV were measured with high resolution at the same energies, and at a scattering angle of 80/degree/. The experimental results were combined with lower-energy values previously obtained by this group to provide a comprehensive data base extending from near the inelastic-scattering threshold to 8 MeV. That data base was interpreted in terms of a coupled-channel model, including the inelastic excitation of one- and two-phonon vibrational levels of the even isotopes of palladium. It was concluded that the palladium inelastic-scattering cross section, at the low energies of interest in assessment of fast-fission-reactor performance, are large (approx.50% greater than given in widely used evaluated fission-product data files). They primarily involve compound-nucleus processes, with only a small direct-reaction component attributable to the excitation of the one-phonon, 2/sup +/, vibrational levels of the even isotopes of palladium. 24 refs., 6 figs.
Date: May 1, 1989
Creator: Chiba, S.; Guenther, P.T. & Smith, A.B.
Partner: UNT Libraries Government Documents Department

Fast-neutron elastic scattering from elemental vanadium

Description: Differential neutron elastic- and inelastic-scattering cross sections of vanadium were measured from 4.5 to 10 MeV. These results were combined with previous 1.5 to 4.0 MeV data from this laboratory, the 11.1 MeV elastic-scattering results obtained at Ohio University, and the reported neutron total cross sections to energies of approx.20.0 MeV, to form a data base which was interpreted in terms of the spherical optical-statistical model. A fit to the data was achieved by making both the strengths and geometries of the optical-model potential energy dependent. This energy dependence was large below approx.6.0 MeV. Above approx.6.0 MeV the energy dependencies are smaller, and similar to those characteristic of global models. Using the dispersion relationship and the method of moments, the optical-model potential energy deduced from 0.0 to 11.1 MeV neutron-scattering data was extrapolated to higher energies and to the bound-state regime. This extrapolation leads to predicted neutron total cross sections that are within 3% of the experimental values throughout the energy range 0.0 to 20.0 MeV. Furthermore, the values of the volume-integral-per-nucleon of the real potential are in excellent agreement with those needed to reproduce the observed binding energies of particle- and hole-states. The latter gives clear evidence of the Fermi surface anomaly. Using only the 0.0 to 11.1 MeV data, the predicted E < O behavior of the strength and radius of the real shell-model Woods-Saxon potential are somewhat different from those obtained by Mahaux and Sartor in their analysis of nuclei near closed shells. 61 refs., 9 figs., 2 tabs.
Date: March 1, 1988
Creator: Smith, A. B.; Guenther, P. T. & Lawson, R. D.
Partner: UNT Libraries Government Documents Department

Nuclear data and measurements series: Ratio of the prompt-fission-neutron spectrum of plutonium 239 to that of uranium 235

Description: The prompt-fission-neutron spectrum resulting from /sup 239/Pu fission induced by 0.55 MeV incident neutrons is measured from 1.0 to 10.0 MeV relative to that of /sup 235/U fission induced by the same incident-energy neutrons. The measurements employ the time-of-flight technique. Energy-dependent ratios of the two spectra are deduced from the measured values over the energy range 1.0 to 10.0 MeV. The experimentally-derived ratio results are compared with those calculated from ENDF/B-V, revision-2, and with results of recent microscopic measurements. Using the ENDF/B-V /sup 235/U Watt parameters for the /sup 235/U spectrum, the experimental measurements imply a ratio of average fission-spectrum energies of /sup 239/Pu//sup 235/U = 1.045 +- 0.003, compared to the value 1.046 calculated from ENDF/B-V, revision 2. 12 refs., 2 figs., 2 tabs.
Date: September 1, 1986
Creator: Sugimoto, M.; Smith, A. B. & Guenther, P. T.
Partner: UNT Libraries Government Documents Department

Fast neutron scattering near shell closures: Scandium

Description: Neutron differential elastic- and inelastic-scattering cross sections are measured from {approx} 1.5 to 10 MeV with sufficient detail to define the energy-averaged behavior of the scattering processes. Neutrons corresponding to excitations of 465 {plus_minus} 23, 737 {plus_minus} 20, 1017 {plus_minus} 34, 1251 {plus_minus} 20, 1432 {plus_minus} 23 and 1692 {plus_minus} 25 keV are observed. It is shown that the observables, including the absorption cross section, are reasonably described with a conventional optical-statistical model having energy-dependent geometric parameters. These energy dependencies are alleviated when the model is extended to include the contributions of the dispersion relationship. The model parameters are conventional, with no indication of anomalous behavior of the neutron interaction with {sup 45}Sc, five nucleons from the doubly closed shell at {sup 40}Ca.
Date: August 1, 1992
Creator: Smith, A. B. & Guenther, P. T.
Partner: UNT Libraries Government Documents Department

Fast-neutron scattering from vibrational palladium nuclei

Description: Neutron total cross sections of elemental palladium are measured from {approx}0.6--4.5 MeV. These results, combined with others previously reported from this laboratory, provide a detailed knowledge of the neutron total cross sections of palladium from {approx}0.1--20 MeV. Differential neutron elastic-scattering cross sections are measured from {approx}1.5--10 MeV in sufficient energy and angle detail to well define the energy-average behavior. Concurrently, neutron inelastic-scattering cross sections are measured from {approx}1.5--8 MeV. Inelastically-scattered neutron groups are observed corresponding to excitations of: 306 {+-} 14, 411 {+-} 47, {approx}494, 791 {+-} 20, 924 {+-} 20, 1,156 {+-} 24, 1,358 {+-} 35, 1,554 {+-} 47 and 1,706 {+-} 59 keV, with additional tentative groups at 1,938 and 2,059 keV. Particular attention is given to the inelastic excitation of the 2{sup +} yrast states of the even isotopes. This broad data base is examined in the context of optical-statistical and coupled-channels models. The resulting model parameters are consistent with systematic trends in this vibrational mass region previously noted at this laboratory, and provide a suitable vehicle for many applications.
Date: October 1, 1993
Creator: Smith, A. B. & Guenther, P. T.
Partner: UNT Libraries Government Documents Department

Nuclear Data and Measurements Series: The energy dependence of the optical-model potential for fast-neutron scattering from bismuth

Description: Neutron differential-elastic-scattering cross sections of bismuth were measured at 0.5 MeV intervals from 4.5 to 10.0 MeV. At each incident energy greater than or equal to40 differential values were obtained, distributed between 18/sup 0/ and 160/sup 0/. The measured data were combined with lower-energy results previously reported from this laboratory, and others available in the literature, to provide a detailed data base extending from 1.5 to 10.0 MeV. This data base was interpreted in terms of the conventional optical-statistical model and also a model inclusive of the surface-peaked real potential predicted by the dispersion relation. Particular attention was given to the energy dependence of the volume-integral-per-nucleon of the real potential, J/sub v/, to see if there was evidence of the Fermi Surface Anomaly. In the range 3.0 to 10.0 MeV the present data indicate that dJ/sub v//dE is essentially constant, with a relatively large negative value of -6.0 to -9.0 fm/sup 3/, depending on the model used in the analysis. Below 3.0 MeV, there is some evidence for a decrease in the magnitude of dJ/dE. However, the effect is very small and it is only when this trend is combined with considerations of the J/sub v/ values needed to give correct bound-state energies that evidence for the Fermi Surface Anomaly emerges. J/sub v/ and the geometry of the optical potentials found for /sup 209/Bi become equal to those needed to explain the high-energy /sup 208/Pb data at about 10.0 MeV. Since dJ/sub v//dE for the latter is smaller in magnitude than for /sup 209/Bi, a change in dJ/sub v//dE is clearly indicated near 10.0 MeV. This may effect the extrapolation of higher-energy and charged-particle potentials into the lower-energy neutron domain. 47 refs., 9 figs.
Date: May 1, 1987
Creator: Smith, A.B.; Guenther, P.T. & Lawson, R.D.
Partner: UNT Libraries Government Documents Department

Fast-neutron total and scattering cross sections of /sup 103/Rh

Description: Fast-neutron total cross sections of /sup 103/Rh are measured with 30 to 50 keV resolutions from 0.7 to 4.5 MeV. Differential elastic- and inelastic-scattering cross sections are measured from 1.45 to 3.85 MeV. Scattered-neutron groups corresponding to excited levels at 334 +- 13, 536 +- 7, 648 +- 25, 796 +- 20, 864 +- 22, 1120 +- 22, 1279 +- 50, 1481 +- 27, 1683 +- 39, 1840 +- 79, 1991 +- 71 and 2050 (tentative) keV are observed. An optical-statistical model is derived from the elastic-scattering results. The experimental values are compared with comparable quantities given in the ENDF/B-V evaluation.
Date: July 1, 1982
Creator: Smith, A.B.; Guenther, P.T. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department

Fast-neutron elastic-scattering cross sections of elemental tin

Description: Broad-resolution neutron-elastic-scattering cross sections of elemental tin are measured from 1.5 to 4.0 MeV. Incident-energy intervals are approx. 50 keV below 3.0 MeV and approx. 200 keV at higher energies. Ten to twenty scattering angles are used, distributed between approx. 20 and 160/sup 0/. The experimental results are used to deduce the parameters of a spherical optical-statistical model and they are also compared with corresponding values given in ENDF/B-V.
Date: July 1, 1982
Creator: Budtz-Jorgensen, C.; Guenther, P.T. & Smith, A.
Partner: UNT Libraries Government Documents Department

Fast neutron scattering near shell closures: Scandium

Description: Neutron differential elastic- and inelastic-scattering cross sections are measured from [approx] 1.5 to 10 MeV with sufficient detail to define the energy-averaged behavior of the scattering processes. Neutrons corresponding to excitations of 465 [plus minus] 23, 737 [plus minus] 20, 1017 [plus minus] 34, 1251 [plus minus] 20, 1432 [plus minus] 23 and 1692 [plus minus] 25 keV are observed. It is shown that the observables, including the absorption cross section, are reasonably described with a conventional optical-statistical model having energy-dependent geometric parameters. These energy dependencies are alleviated when the model is extended to include the contributions of the dispersion relationship. The model parameters are conventional, with no indication of anomalous behavior of the neutron interaction with [sup 45]Sc, five nucleons from the doubly closed shell at [sup 40]Ca.
Date: August 1, 1992
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Fast-neutron interaction with collective cadmium nuclei

Description: Differential neutron elastic-scattering cross sections of elemental cadmium are measured from [approx] 1.5 to 10 MeV. From [approx] 1.5 to 3.0 MeV the measurements are made at [approx] 100 keV incident-neutron energy intervals and at 10 scattering angles distributed between [approx] 200 and 160[degree]. From 3 to 4 MeV the measurements are made at [approx] 200 MeV intervals and at 20 angles. Above 4 MeV the incident-energy interval is [approx] 0.5 MeV with [ge] 40 differential values at each incident energy, distributed between [approx] 18 and 160[degree]. Concurrently, differential cross sections for the excitation of observed levels'' at 0.589 [plus minus] 0.047, 1.291 [plus minus] 0.066 and 1.839 [plus minus] 0.57 MeV are determined, with attention to the direct excitation of the yrast 2[sup +] levels of the even isotopes ([approx] 75% abundant) and of the 3/2[sup +] and 5/2[sup +] levels of the odd isotopes ([approx] 75% abundant). Optical-statistical, dispersive-optical and coupled-channels interpretations are carried out and comparisons made with regional'' and global'' parameters. Consideration is given to the fundamental nature of the real potential in the vicinity of the Fermi Surface with implications on the equation of state and the reduced mass, in the context of the dispersive optical model.
Date: November 1, 1992
Creator: Smith, A.B. & Guenther, P.T.
Partner: UNT Libraries Government Documents Department

Fast-neutron total and scattering cross sections of niobium

Description: Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V.
Date: July 1, 1982
Creator: Smith, A.B.; Guenther, P.T. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department