Recent Articles

${}^{10}B$ from ${}^{9}{Be} ({}^{3}{He}, d)$

L. Bland and H. T. Fortune

Phys. Rev. C 21, 11 (1980) - Published 1 January, 1980

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Angular distributions for the reaction ${}^{9}{Be} ({}^{3}{He}, d)$ have been measured for all levels below 6.8 MeV in ${}^{10}B$ . Data confirm that states at 6.13 and 6.57 MeV, previously assigned $J^{π} = 3^{-} and {(4)}^{-}$ , respectively, have the same parity. Their strengths are consistent with their being the $3^{-}$ and $4^{-}$ states expected in this region of excitation.

NUCLEAR REACTION ${}^{9}{Be} ({}^{3}{He}, d)$ , $E = 18.0$ MeV. ${}^{10}B$ levels deduced $l$ , $π$ , $S_{p}$ . DWBA analysis.

Isomeric transitions in ${}^{100}{Tc}$

M. Bini, A. M. Bizzeti-Sona, P. Blasi, M. Lorini, and N. Taccetti

Phys. Rev. C 21, 116 (1980) - Published 1 January, 1980

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Low-lying levels of ${}^{100}{Tc}$ have been investigated with the reaction ${}^{100}{Mo} (p, n γ) {}^{100}{Tc}$ in the energy range $4 MeV \leq E_{p} \leq 6.8 MeV$ . Gamma-ray cascades have been studied by means of $γ - γ$ coincidences. Two isomeric states have been identified, namely the 200.6 keV ( $4^{+}$ ) state with $τ_{m} = 11.8 \pm 0.1$ μs and the 243.9 keV ( $6^{+}$ ) state with $τ_{m} = 4.7 \pm 0.3$ μs. An upper limit $τ_{m} \leq 4$ ns has been assigned for the mean life of seven other levels.

NUCLEAR REACTIONS ${}^{100}{Mo} (p, n γ)$ , $E_{p} = 4 - 6.8$ MeV, pulsed beam; measured $E_{γ}$ , $γ - γ$ coincidences, delayed $γ$ . Two ${}^{100}{Tc}$ isomers observed, deduced life-times. Enriched target.

Neutron-hole distributions in ${}^{111, 115, 119}{Sn}$ as observed in the ( ${}^{3}{He}, α$ ) reaction

E. Gerlic, G. Berrier-Ronsin, G. Duhamel, S. Galès, E. Hourani, H. Langevin-Joliot, M. Vergnes, and J. Van de Wiele

Phys. Rev. C 21, 124 (1980) - Published 1 January, 1980

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The energy spectra of residual ${}^{111, 115, 119}{Sn}$ nuclei have been studied with 38 keV resolution, up to excitation energies of the order of 16 MeV, using the ( ${}^{3}{He}, α$ ) reaction at 39 MeV. Complete angular distributions have been obtained for the ${}^{116}{Sn} ({}^{3}{He}, α) {}^{115}{Sn}$ reaction; two angles were measured for the other isotopes. Several new levels or groups are observed up to ∼ 3.5 MeV in the three isotopes, owing to the momentum matching conditions. Spectroscopic factors are determined for all observed levels up to 3.71 MeV in ${}^{115}{Sn}$ and for the low-lying strongly populated levels with known $J^{π}$ in ${}^{111, 119}{Sn}$ . The fragmentation of the $l = 4, 5$ valence hole strengths and the excitation of levels with anomalous spins and parities in the intermediate energy region in ${}^{115}{Sn}$ are discussed in terms of weak-coupling and two-step coupled channels calculations. The fine structure previously reported for the $1 g_{\frac{9}{2}}$ hole orbital in ${}^{115}{Sn}$ is clearly confirmed and enhanced in the present experiment. The fragmentation of this orbital is observed for the first time in ${}^{111}{Sn}$ , between 3.4 and 5.2 MeV and in ${}^{119}{Sn}$ , though to a lesser extent, between 3.8 and 6.5 MeV. In the fine structure region the $1 g_{\frac{9}{2}}$ hole strength is found to decrease from 62% to 43% and 28% in ${}^{111}{Sn}$ , ${}^{115}{Sn}$ , and ${}^{119}{Sn}$ , respectively; theoretical calculations do not explain these experimental strengths and fragmentations. The first ${9 / 2}^{+}$ , ${1 / 2}^{-}$ , ${3 / 2}^{-}$ isobaric analog states are identified in ${}^{111}{Sn}$ . Previously unreported, weakly populated isobaric analog states are also found in ${}^{115}{Sn}$ and ${}^{119}{Sn}$ . The energies and widths are measured. The spectroscopic factors and isospin splitting of these states are discussed in the framework of the Lane coupled-channels formalism for the neutron form factor.

NUCLEAR REACTIONS ${}^{112, 116, 120}{Sn} ({}^{3}{He}, α)$ $E = 39$ MeV; measured $σ (E_{α}, θ)$ ${}^{111, 115, 119}{Sn}$ deduced levels, $E_{x}$ , $l$ , ${(J)}^{π}$ , $C^{2} S$ ; zero-range DWBA and two-step process analysis; inner shells and isobaric analog states analysis: enriched targets, magnetic spectrometer.

NUCLEAR STRUCTURE unified model calculations.

Comparison of giant multipole resonances of multipolarity $E 1$ to $E 4$ in ${}^{58}{Ni} (T_{0} = 1)$ and ${}^{60}{Ni} (T_{0} = 2)$ with inelastic electron scattering

R. Pitthan, G. M. Bates, J. S. Beachy, E. B. Dally, D. H. Dubois, J. N. Dyer, S. J. Kowalick, and F. R. Buskirk

Phys. Rev. C 21, 147 (1980) - Published 1 January, 1980

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The cross section for electron scattering from the isotopes ${}^{58}{Ni}$ and ${}^{60}{Ni}$ has been measured with electrons of 102 MeV at scattering angles of 45, 60, 75, 90, and 105° between 3 and 50 MeV excitation energy. Resonances or resonancelike structures at approximate excitation energies of (7-8) MeV, 13 MeV, (16-17) MeV, (18-19) MeV, 27 MeV, 32 MeV, and 40 MeV were classified on the basis of their momentum transfer dependence and discussed in the framework of the shell model. Difficulties in the extraction of the cross section and model dependencies of the interpretation are discussed.

NUCLEAR REACTIONS ${}^{58}{Ni} (e, e^{'})$ and ${}^{60}{Ni} (e, e^{'})$ , $E_{0} = 102$ MeV. Measured $\frac{d^{2} σ}{d Ω d E_{x}}$ , bound and continuum states (giant resonances). Deduced multipolarity, reduced matrix element $B (E λ)$ , sum rule exhaustion of giant resonances, total width of continuum and clustered states.

$m$ -substate populations in resonant heavy-ion reactions

J. R. Beene, R. M. DeVries, D. Shapira, and M. R. Clover

Phys. Rev. C 21, 167 (1980) - Published 1 January, 1980

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We have employed the line shape analysis technique to study nuclear spin alignment produced in the ${}^{12}C$ + ${}^{16}O$ reaction populating the $2^{+}$ 4.43-MeV state in ${}^{12}C$ . We present excitation functions of $m$ -substate population $P (m)$ measured in the range $E_{c . m .} = 19 - 22.6$ MeV and detailed angular distributions of $P (m)$ obtained at $E_{c . m .} = 21.7, 21.9, and 22.3$ MeV. Results have been analyzed in terms of a single resonance with sharp spin in the compound nucleus and found to contradict previous spin assignment based on studies of angular distributions of cross section in the $E_{c . m .} \approx 22 to 22.6$ MeV region.

NUCLEAR REACTIONS ${}^{12}C$ ( ${}^{16}O$ , ${}^{12}C^{*}$ ) ${}^{16}O$ , $E_{lab} = 45 - 53$ MeV. Measured $σ (E; E {}^{12}C^{*}, θ)$ , deduced ${}^{12}C^{*}$ (4.43 MeV, $2^{+}$ ) spin alignment ( $σ (E; m, θ)$ ). ${}^{16}O$ + ${}^{12}C$ resonances, deduced $J$ , $π$ .

Search for fusion oscillations in the ${}^{16}O$ + ${}^{28}{Si}$ system

R. R. Betts, M. M. Hindi, S. B. DiCenzo, and P. D. Parker

Phys. Rev. C 21, 175 (1980) - Published 1 January, 1980

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The yields of gamma rays from evaporation residues following the fusion of ${}^{16}O$ + ${}^{28}{Si}$ have been measured over the energy range 50-65 MeV in a search for structure similar to that found in the backward angle elastic scattering of this system. No such structure is seen at a level of about 4% of the total fusion cross section.

[NUCLEAR REACTIONS ${}^{16}O$ + ${}^{28}{Si}$ fusion, measured $σ (E, A, Z)$ .]

Mechanisms of production of fast particles with $Z = 1, 2$ in ${}^{6}{Li}$ -induced reactions far above the Coulomb barrier

C. M. Castaneda, H. A. Smith, Jr., P. P. Singh, and H. Karwowski

Phys. Rev. C 21, 179 (1980) - Published 1 January, 1980

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Various mechanisms for the production of fast, beam-velocity particles have been explored using a 12.5 MeV/nucleon ${}^{6}{Li}$ beam, with special emphasis on results from a ${}^{197}{Au}$ target. Energy spectra and angular distributions of fast, $Z = 1, 2$ products revealed an $A^{\frac{1}{3}}$ target mass dependence of the individual total yields which is characteristic of the surface mechanisms. Relative fragment yields were essentially independent of the target mass and appear to depend upon the momentum distributions of the different cluster substructures of ${}^{6}{Li}$ . Particle- $γ$ coincidences reflected the $Q$ -optimum transfer of a beam-velocity $α$ or $d$ fragment, initiating a (fragment, $xn γ$ )-like reaction, and which accounts for approximately 13% of the singles beam-velocity particle production. In-plane $α - d$ coincidences could be divided roughly equally between two-step (sequential) and one-step projectile breakup. Alpha-proton coincidences suggested the strong presence of neutron transfer, forming unstable ${}^{5}{Li}$ which subsequently breaks up into $α + p$ . The cross section from correlated $α + d$ and $α + p$ production accounts for at least 50% of the singles fast-particle production. Other possible mechanisms are also discussed.

NUCLEAR REACTIONS ${}^{197}{Au}$ , ${}^{56}{Fe} ({}^{6}{Li}, X)$ $E = 75$ MeV, measured particle energy spectra and angular distributions. ${}^{197}{Au} ({}^{6}{Li}, X)$ measured two-dim $α - d$ , $α - p$ , $α - γ$ , $d - γ$ , $p - γ$ coincident energy and angular correlations. Deduced $σ_{X} (θ)$ , $σ_{tot} (X)$ , reaction mechanisms.

Parametrization of $\frac{N}{D}$ input

M. G. Fuda, B. A. Girard, and J. S. Whiting

Phys. Rev. C 21, 18 (1980) - Published 1 January, 1980

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A modified version of the usual single channel $\frac{N}{D}$ equations is presented, which makes possible a mathematically sound parametrization of the effect of those distant parts of the left hand cut and right hand cut for which the discontinuities are not known. A conformal mapping technique is used to develop a generally valid parametrization involving only real parameters. An application to the Phillips plot of triton energy versus doublet scattering length is given so as to demonstrate the superiority of the present scheme over ones used earlier by us.

NUCLEAR REACTIONS Parametrization of unknown discontinuities in $\frac{N}{D}$ equations, Phillips plot.

Resonances in ${}^{12}C$ + ${}^{12}C$ inelastic scattering to the $0^{+}_{2}$ , $3^{-}_{1}$ , and $4^{+}_{1}$ states

B. R. Fulton, T. M. Cormier, and B. J. Herman

Phys. Rev. C 21, 198 (1980) - Published 1 January, 1980

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Excitation functions for ${}^{12}C$ + ${}^{12}C$ inelastic scattering to the $0^{+}_{2}$ , $3^{-}_{1}$ , and $4^{+}_{1}$ levels have been measured over the energy range of the gross structure resonances seen in the single and mutual $2^{+}_{1}$ inelastic scattering channels. Resonant structure is observed which is similar to, but more fragmented than, that in the low lying channels. The general features of the results are in agreement with the band crossing model of the ${}^{12}C$ + ${}^{12}C$ interaction, but detailed comparison indicates some serious discrepancies. Particularly, a strong resonance in the $0^{+}_{2}$ channel violates the band crossing hypothesis.

NUCLEAR REACTIONS ${}^{12}C$ ( ${}^{12}C$ , ${}^{12}C$ ) ${}^{12}C^{*}$ ; $E_{lab} = 44 to 80$ MeV; $θ_{lab} = 15 ° to 25 °$ ; Measured $σ (θ, E)$ for $0^{+}_{2}$ , $3^{-}_{1}$ , and $4^{+}_{1}$ ; Deduced energies and widths of intermediate structures in ${}^{24}{Mg}$ .

Equilibrium statistical treatment of angular momenta associated with collective modes in fission and heavy-ion reactions

Luciano G. Moretto and Richard P. Schmitt

Phys. Rev. C 21, 204 (1980) - Published 1 January, 1980

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The angular momentum effects in deep inelastic processes and fission have been studied in the limit of statistical equilibrium. The model consists of two touching liquid drop spheres. Angular momentum fractionation has been found to occur along the mass asymmetry coordinate. If neutron competition is included (i.e., in compound nucleus formation and fission), the fractionation occurs only to a slight degree, while extensive fractionation is predicted if no neutron competition occurs (i.e., in "fusion-fission" without compound nucleus formation). Thermal fluctuations in the angular momentum are predicted to occur due to degrees of freedom which can bear angular momentum such as wriggling, tilting, bending, and twisting. The coupling of relative motion to one of the wriggling modes, leading to fluctuations between orbital and intrinsic angular momentum, is considered first. Next the effect of the excitation of all the collective modes on the fragment spin is treated. General expressions for the first and second moments of the fragment spins are derived as a function of total angular momentum and the limiting behavior at large and small total angular momentum is examined. Furthermore, the effect of collective mode excitation on the fragment spin alignment is explored and is discussed in light of recent experiment. The relevance of the present study to the measured first and second moments of the $γ$ -ray multiplicities as well as to sequential fission angular distributions is illustrated by applying the results of the theory to a well studied heavy-ion reaction.

NUCLEAR REACTIONS Studied angular momentum fractionation along mass asymmetry mode. Investigated effect of collective rotational modes on fragment spins. Equilibrium statistical treatment.

Quadrupole contributions to ${}^{10, 11}B$ + ${}^{16}O$ elastic scattering

L. A. Parks, D. P. Stanley, L. H. Courtney, and K. W. Kemper

Phys. Rev. C 21, 217 (1980) - Published 1 January, 1980

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Elastic scattering angular distributions have been measured for the systems ${}^{10}B$ + ${}^{16}O$ at $E_{L} = 33.7, 41.6, and 49.5$ MeV and ${}^{11}B$ + ${}^{16}O$ at $E_{L} = 41.6 and 49.5$ MeV. The ${}^{10}B$ and ${}^{11}B$ data are oscillatory and similar for angles less than 50° c.m. For angles greater than 50° c.m., the oscillations in the ${}^{10}B$ data are damped and the data stop decreasing with increasing angle. Elastic scattering angular distributions have been calculated for ${}^{10, 11}B$ + ${}^{16}O$ with the coupling to the ground-state quadrupole moment included explicitly. Potentials which describe the scattering are extracted with the double folding model. It is found that the quadrupole coupling is necessary to explain the difference in ${}^{10}B$ and ${}^{11}B$ scattering from ${}^{16}O$ .

NUCLEAR REACTIONS ${}^{16}O$ ( ${}^{10}B$ , ${}^{10}B$ ) ${}^{16}O$ , $E_{L} = 33.7, 41.6, and 49.5$ MeV, ${}^{16}O$ ( ${}^{11}B$ , ${}^{11}B$ ) ${}^{16}O$ , $E_{L} = 41.6 and 49.5$ MeV. Measured $σ (θ)$ , deduced Woods-Saxon, and double-folding model parameters. Coupled channels calculations for the ground-state quadrupole moment contributions.

Core coupled states in ${}^{145}{Eu}$

D. Bazzacco, A. M. I. Haque, K. O. Zell, P. von Brentano, and C. Protop

Phys. Rev. C 21, 222 (1980) - Published 1 January, 1980

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New high-spin states in ${}^{145}{Eu}$ up to 4 MeV excitation energy have been studied with the methods of the inbeam $γ$ -spectroscopy bombarding enriched ${}^{142}{Nd}$ targets with ${}^{6}{Li}$ ions. For most of them a configuration is proposed in terms of weak coupling one proton hole to the ${}^{146}{Gd}$ core or one proton particle to the ${}^{144}{Sm}$ core.

NUCLEAR REACTIONS ${}^{142}{Nd} ({}^{6}{Li}, 3 n γ)$ , $E = 25 - 33$ MeV; measured $E_{γ}$ , $I_{γ}$ , $σ (E, E_{γ}, θ)$ , $γ - γ$ coin. ${}^{145}{Eu}$ deduced levels $J$ , $π$ . Enriched targets. Ge-Li detectors.

Statistical model calculations in heavy ion reactions

A. Gavron

Phys. Rev. C 21, 230 (1980) - Published 1 January, 1980

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Results of various fusion experiments with heavy ions are compared with predictions of statistical model calculations. In some reactions there is evidence for nonstatistical effects based on significant discrepancies between the calculations and the experimental results. Alternative explanations of these discrepancies are considered.

[NUCLEAR REACTIONS HI ( $xn γ$ ), statistical model calculations.]

Product yields for the photofission of ${}^{235}U$ with 12-, 15-, 20-, 30-, and 70-MeV bremsstrahlung

E. Jacobs, H. Thierens, D. De Frenne, A. De Clercq, P. D'hondt, P. De Gelder, and A. J. Deruytter

Phys. Rev. C 21, 237 (1980) - Published 1 January, 1980

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The mass distributions for the photofission of ${}^{235}U$ using bremsstrahlung with end-point energy of 12, 15, 20, 30, and 70 MeV were determined by $γ$ spectrometry of fission product catcher foils. Smoothly varying curves without fine structure were obtained. A third hump in the symmetric region is not present. Several fractional independent chain yields in the mass region 126-140 were measured and the corresponding most probable charges $Z_{p} (E_{e})$ were deduced. A comparison with the charge expected from the unchanged charge density hypothesis is made and an influence of the 50-proton shell on the behavior of the $Z_{p}$ function is observed. Except in this mass region the determined $Z_{p} (E_{e})$ values are very well described by the empirical relation of Nethaway. From the isomeric ratios of ${}^{126}{Sb}^{g} - {}^{126}{Sb}^{m}$ , ${}^{128}{Sb}^{g} - {}^{128}{Sb}^{m}$ , and ${}^{131}{Te}^{g} - {}^{131}{Te}^{m}$ average initial fragment spins are calculated using a statistical model analysis. The values increase with increasing end-point energy of the bremsstrahlung.

NUCLEAR REACTIONS, FISSION ${}^{235}U (γ, F)$ , $E_{γ max} = 12, 15, 20, 30, 70$ MeV; measured: fragment $γ$ -ray spectra; deduced: mass distributions, most probable charges, isomeric ratios, average initial fragment spins.

( $π^{\pm}, x n$ ) reactions

L. B. Church and A. A. Caretto, Jr.

Phys. Rev. C 21, 246 (1980) - Published 1 January, 1980

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Cross sections for the formation of the ${}^{76}{Ge} {(π^{+}, x n)}^{76 - x} As$ and the ${}^{76}{Se} {(π^{-}, x n)}^{76 - x} As$ reaction products were determined for values of $x$ up to six for both 100 and 180 MeV pions. The $π^{-}$ induced cross sections were consistently higher than those induced by $π^{+}$ for all nonzero values of $x$ . Both the $π^{-}$ and $π^{+}$ induced cross sections appear to reach a maximum value when $x$ equals 2 or 3. The results are compared to predictions based on cascade-evaporation calculations and discussed in terms of possible mechanisms. Combining the experimental results for $x = 5 and 6$ with these calculations it was concluded that no significant difference exists in the excitation energy spectrum following $π^{+}$ or $π^{-}$ interaction.

NUCLEAR REACTIONS ${}^{76}{Ge} {(π^{+}, x n)}^{76 - x} As$ : $E_{π^{+}} = 100 and 180$ MeV; ${}^{76}{Se} {(π^{-}, x n)}^{76 - x} As$ , $E_{π^{-}} = 100 and 180$ MeV; product formation cross sections.

Determination of the optical potential for elastic proton scattering on ${}^{6}{Li}$ , ${}^{12}C$ , and ${}^{14}N$ at 144 MeV

G. L. Moake and P. T. Debevec

Phys. Rev. C 21, 25 (1980) - Published 1 January, 1980

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Elastic scattering cross sections have been measured for ${}^{14}N$ with 144 MeV protons at laboratory angles between 5° and 58°. Optical model parameters for ${}^{14}N$ were determined from these data, and parameters for ${}^{6}{Li}$ and ${}^{12}C$ were determined from previously existing data at 144 MeV.

NUCLEAR REACTIONS ${}^{14}N (p, p) {}^{14}N$ , $E_{p} = 144$ MeV; measured $σ (θ)$ ; optical model analysis for ${}^{14}N$ and existing ${}^{6}{Li}$ and ${}^{12}C$ data.

Elastic and inelastic scattering of 162 MeV pions by ${}^{28}{Si}$ , ${}^{58}{Ni}$ , and ${}^{208}{Pb}$

C. Olmer, D. F. Geesaman, B. Zeidman, S. Chakravarti, T. -S. H. Lee, R. L. Boudrie, R. H. Siemssen, J. F. Amann, C. L. Morris, H. A. Thiessen, G. R. Burleson, M. J. Devereux, R. E. Segel, and L. W. Swenson

Phys. Rev. C 21, 254 (1980) - Published 1 January, 1980

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Angular distributions for the elastic and inelastic scattering of 162 MeV $π^{+}$ and $π^{-}$ by Si, ${}^{58}{Ni}$ , and ${}^{208}{Pb}$ have been measured. The elastic scattering data are fitted with optical model calculations in configuration space. Momentum-space optical-model calculations qualitatively reproduce the elastic scattering data, but substantially better agreement can be obtained if suitable modifications to the model are made. Distorted-wave impulse approximation calculations of the inelastic scattering, using both configuration-space and momentum-space models, generally reproduce the experimental data.

NUCLEAR REACTIONS ${}^{28}{Si} (π, π^{'})$ , ${}^{58}{Ni} (π, π^{'})$ , ${}^{208}{Pb} (π, π^{'})$ , $E = 162$ MeV, measured $\frac{d σ}{d Ω}$ ; optical potential and DWIA collective model analyses.

Pion-nucleus scattering using finite binding potentials

M. Silver and N. Austern

Phys. Rev. C 21, 272 (1980) - Published 1 January, 1980

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A nonperturbative treatment of finite binding potentials in pion-bound nucleon scattering is developed. Coupled differential equations in configuration space are derived from a model wave function broken into two parts. Coordinates from the source of binding to the pion and to the nucleon are used in the elastic channel, while pion-nucleon center-of-mass coordinates are used for the excited channels. The excited channel equations are solved in closed form using a separable nonlocal pion-nucleon interaction. When the solution is inserted into the elastic channel equation, a relativistically modified single-particle equation for the elastically scattered meson is derived, which features an optical potential with both local and nonlocal parts. This model is used in conjunction with first order multiple scattering theory to construct pion-nucleus scattering. In the present application of the model the assumed pion-nucleon interaction is taken to be $s$ wave with threshold $p$ -wave behavior. The region around the 33 resonance is numerically studied for both the three-body model and for pions on ${}^{16}O$ . A consistent, inclusive treatment of many effects familiar from earlier work is obtained. Results from the three-body calculation show that the peak cross section is shifted upwards by about the binding energy of the struck nucleon. However, nonlinear effects drive the peak downwards when the three-body model is incorporated in the pion-nucleus formalism, so that several bound nucleons simultaneously scatter the meson. Effects of this kind are not expected to be sensitive to the use of an artificial $l = 0 π N$ interaction. Resonances caused by the binding potential are found to be important in both the three-body and the $π - {}^{16}O$ ${}^{16}O$ calculations. This suggests significant corrections to an impulse approximation approach.

NUCLEAR REACTIONS ${}^{16}O (π, π)$ , three-body model of $π$ -nucleon interaction, $σ_{T} (E)$ calculated.

Giant multipole resonances in the deformed fissionable nucleus ${}^{238}U$

R. Pitthan, F. R. Buskirk, W. A. Houk, and R. W. Moore

Phys. Rev. C 21, 28 (1980) - Published 1 January, 1980

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The deformed, fissionable nucleus ${}^{238}U$ was studied with inelastic scattering of 87.5 MeV electrons between 5 and 40 MeV excitation energy with inelastic momentum transfers ranging from 0.32 ${fm}^{- 1}$ to 0.58 ${fm}^{- 1}$ for an excitation energy of 15 MeV. Resonance cross sections extracted were compared with distorted-wave Born-approximation calculations using the Goldhaber-Teller, Steinwedel-Jensen, and Myers-Swiatecki models of the giant resonance. It is demonstrated that up to the first minimum of the form factor the cross section is nearly completely determined by one parameter, the transition radius $R_{tr}$ . Using the known systematics of various multipole resonances in other, nonfissionable nuclei as a guide, it was found that the assumed ground state radius of ${}^{238}U$ had to be enlarged by about 10% for all multipolarities, to bring the strength found into agreement with the systematics and with other experiments in ${}^{238}U$ . In particular, while the model-independent values for position and width of the giant dipole resonance agree well with photon experiments, a scaled version of the Myers-Swiatecki model had to be used to produce agreement in strength. Similarly a scaled Goldhaber-Teller model was used for the isoscalar $E 2$ resonance at 9.9 MeV. The situation for the isovector states above the giant dipole resonance, $E 2$ , and $E 3$ (or $E 0$ is even more complicated. It is argued that with proper caution and consideration of other available data the use of the collective models mentioned above may give valuable insight into the charge distribution of ${}^{238}U$ at higher excitation energies.

NUCLEAR REACTIONS ${}^{238}U (e, e^{'})$ , $E_{0} = 87.5$ MeV. Measured $\frac{d^{2} σ}{d Ω d E_{x}}$ , bound and continuum states (giant resonances). Deduced multipolarity, reduced matrix element $B (E λ)$ , radiative width $Γ_{γ}^{0}$ , sum rule exhaustion of giant resonances, total width of continuum and clustered states.

Inelastic pion scattering for $1 p$ -shell targets

T. -S. H. Lee and D. Kurath

Phys. Rev. C 21, 293 (1980) - Published 1 January, 1980

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Inelastic scattering of pions with energy near the (3,3) resonance is calculated with a distorted-wave impulse approximation formulated in momentum space. Results for all $1 p$ -shell targets are given and compared to existing data. Strong transitions are dominated by quadrupole amplitudes, and enhancement factors consistent with observed $B (E 2)$ values are needed to attain agreement with observed cross sections in these cases. The sensitivity of pion scattering to isospin effects is noted. This distorted-wave impulse approximation approach appears to offer a reasonable interpretation of inelastic pion scattering.

NUCLEAR REACTIONS, NUCLEAR STRUCTURE ( $π, π^{'}$ ) $E_{π} \approx 120 to 220$ MeV; $1 p$ -shell targets, theoretical $\frac{d σ}{d Ω}$ based on DWIA in momentum space; effect of nuclear structure and sensitivity to isospin.

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Physical Review C

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${}^{10}B$ from ${}^{9}{Be} ({}^{3}{He}, d)$

Isomeric transitions in ${}^{100}{Tc}$

Neutron-hole distributions in ${}^{111, 115, 119}{Sn}$ as observed in the ( ${}^{3}{He}, α$ ) reaction

Comparison of giant multipole resonances of multipolarity $E 1$ to $E 4$ in ${}^{58}{Ni} (T_{0} = 1)$ and ${}^{60}{Ni} (T_{0} = 2)$ with inelastic electron scattering

$m$ -substate populations in resonant heavy-ion reactions

Search for fusion oscillations in the ${}^{16}O$ + ${}^{28}{Si}$ system

Mechanisms of production of fast particles with $Z = 1, 2$ in ${}^{6}{Li}$ -induced reactions far above the Coulomb barrier

Parametrization of $\frac{N}{D}$ input

Resonances in ${}^{12}C$ + ${}^{12}C$ inelastic scattering to the $0^{+}_{2}$ , $3^{-}_{1}$ , and $4^{+}_{1}$ states

Equilibrium statistical treatment of angular momenta associated with collective modes in fission and heavy-ion reactions

Quadrupole contributions to ${}^{10, 11}B$ + ${}^{16}O$ elastic scattering

Core coupled states in ${}^{145}{Eu}$

Statistical model calculations in heavy ion reactions

Product yields for the photofission of ${}^{235}U$ with 12-, 15-, 20-, 30-, and 70-MeV bremsstrahlung

( $π^{\pm}, x n$ ) reactions

Determination of the optical potential for elastic proton scattering on ${}^{6}{Li}$ , ${}^{12}C$ , and ${}^{14}N$ at 144 MeV

Elastic and inelastic scattering of 162 MeV pions by ${}^{28}{Si}$ , ${}^{58}{Ni}$ , and ${}^{208}{Pb}$

Pion-nucleus scattering using finite binding potentials

Giant multipole resonances in the deformed fissionable nucleus ${}^{238}U$

Inelastic pion scattering for $1 p$ -shell targets

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