The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^3{}_{}{}^{}\mathrm{He}n){}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ cross section at 910 MeV was measured by using a Ge(Li) gamma spectrometer to determine the disintegration rate and measuring the incident flux by means of a scintillator telescope. Cross sections for the production of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ in C and Al and for the production of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ in Al are then determined using the measured cross section as a monitor.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^3{}_{}{}^{}\mathrm{He}n){}_{}{}^{11}{}_{}{}^{}\mathrm{C}$. Measurement of the cross section at 910 MeV.

Looked at from a model-independent point of view, the existence of a non-zero first class induced tensor form factor appears to provide a substantial contribution to the observed $\mathrm{ft}$ asymmetry in mirror Gamow-Teller beta decays. However, we demonstrate that, when analyzed in terms of the impulse approximation, this is only a negligibly small effect.

RADIOACTIVITY Calculated contribution to $\mathrm{ft}$ asymmetry from first class induced tensor.

The interacting boson approximation is extended to include equivalent proton and neutron bosons and the spectra of ${}_{}{}^{196,198,202}{}_{}{}^{}\mathrm{Hg}$ are discussed in terms of the O(6) group appropriate to this mass region.

NUCLEAR STRUCTURE IBA model O(6) limit with equivalent $p-n$ bosons, ${}_{}{}^{196,198,202}{}_{}{}^{}\mathrm{Hg}$ calculated levels, $J$, $\pi$.

The consequences of excitation energy equilibrium between the two partners in a deep-inelastic collision are explored. In this work we calculate the second moment of the excitation energy distribution and demonstrate the effects of the fluctuations on evaporated particle spectra and the correlation created in the numbers of evaporated particles from the deep-inelastic fragments.

NUCLEAR REACTIONS Studied excitation energy division in deep-inelastic collisions, first and second moments. Calculated influence of fluctuations on evaporated particle spectra, correlations in evaporated particle number. Statistical equilibrium model, Monte Carlo statistical evaporation.

The need to include the phase space factor in the analysis of α breakup spectra according to Fermi's Golden Rule is indicated. The importance of the number of particles present in the final state is exemplified by a model calculation for proton, deuteron, and triton spectra produced by the breakup of 160 MeV alphas on zirconium.

NUCLEAR REACTIONS phase space factor, model alpha breakup spectra for $\mathrm{Zr}(\alpha ,xp)$, $\mathrm{Zr}(\alpha ,xd)$, and $\mathrm{Zr}(\alpha ,xt)$ reactions at $E_{\alpha }=160\mathrm{}$ MeV.

The effects of nuclear parity violation on atomic deuterium parity violation experiments and elastic electron-deuteron scattering are treated. Since the hadronic isoscalar axial neutral weak current is very small in the Weinberg-Salam theory, the effects of nuclear parity violation are important in parity violation measurements which test the vector coupling to the electron and the axial (isoscalar) coupling to the deuteron. Such measurements have been proposed as a test of the Weinberg-Salam theory. A consistent treatment of the effect requires a modification of the impulse approximation to restore gauge invariance. It is found that parity nonconservation caused by nuclear parity violation is of the same order of magnitude as that caused by the anomaly-induced isoscalar axial neutral weak current or as that due to radiative corrections.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}(e,e^{\prime }){}_{}{}^2{}_{}{}^{}\mathrm{H}$; parity-violating form factors, "nucleon-only" impulse approximation constrained by gauge invariance; induced isoscalar axial neutral weak current, radiative corrections.

Recent calculations have shown that multiphoton transitions in a nucleus that involve a $\gamma$-ray photon could be induced by intense fields of optical radiation. The effect of such transitions was predicted to be a shift of the $\gamma$-ray energy by the addition or subtraction of the energy of the optical photon. A literature search has shown that such optical sidebands have been observed in certain instances on the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer line at 14 keV and not satisfactorily explained by conventional models. This work reports the formulation and evaluation of the multiphoton model for the values of experimental variables appropriate to those experiments. Using no fitted parameters, remarkable agreement was obtained between the predictions of the multiphoton theory and the previously reported results.

NUCLEAR REACTIONS Calculated $B$ for multiphoton absorption; $\gamma$ plus radio-frequency photons.

Neutron total non-elastic cross sections have been obtained from transmission measurements of 40.3 and 50.4 MeV neutrons on C, O, Ca, and Fe. The results agree within error bars with proton data on the same nuclei. The data are well represented by the relation ${\sigma }_{\mathrm{non}}=\pi {(r_0{A}^{\frac{1}{3}}+\lambda )}^2$, where $r_0=1.21\mathrm{}\pm 0.03$ fm. Comparisons of ${\sigma }_{\mathrm{non}}$ with optical model calculations for C and O show a preference for the parameters of Bassel and Herling, while for Ca both the parameter sets of Patterson and those of Becchetti and Greenlees work reasonably well. None of the parameter sets is entirely satisfactory for Fe. Implications of these data for the isospin dependence of the optical model are discussed.

NUCLEAR REACTIONS C, O, Ca, and $\mathrm{Fe}+n$, $E_n=40.3\mathrm{} \mathrm{and} 50.4$ MeV. Inferred neutron total elastic and non-elastic cross sections. Natural targets.

Accurate and extensive measurements have been made of the differential cross sections for the elastic scattering of protons from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ targets over an energy range of 80-180 MeV, in the angular range from about 6° to about 90° (to 126° for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ at 135 MeV) in 0.5° to 2.5° steps. The most prominent general feature of the data, namely strong damping of the diffractive oscillations in the mid-angle region (roughly 30-60°), was found to arise from the complex spin-orbit interaction which has a considerably greater influence on the differential cross section at these energies than at lower energies. These data, together with data of comparable quality from other sources in the energy range 60-180 MeV, were analyzed in terms of a 10-parameter phenomenological optical-model potential using relativistic kinematics and a relativistic extension of the Schrödinger equation. Analyses with various parameter constraints were performed. A logarithmic energy dependence was found for the strengths of the real potentials (central and spin-orbit terms); the corresponding imaginary potentials were found to be essentially independent of energy. While individual model parameters were generally not uniquely defined by the cross section data, volume integrals of the central potentials were well determined. The spin-orbit parameterization was found to be relatively more uncertain, despite the enhanced sensitivity of the cross section to spin dependent terms in the potential at these energies and the inclusion of some existing polarization data in the analysis. Some features of the phenomenological potentials were compared with the predictions of microscopic potential models, and certain aspects of the proton-nucleus interaction at the higher energies have been found to be describable in terms of the free nucleon-nucleon interaction.

NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}\mathrm{}(p,p)\mathrm{}$, $E_p=79.9,121.2,160.0,182.4$ MeV; ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}\mathrm{}(p,p)\mathrm{}$, $E_p=79.8,135.1,160.0,180.0$ MeV; ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}\mathrm{}(p,p)\mathrm{}$, $E_p=80.2,135.1,160.0$ MeV; measured $\sigma \left(\theta \right)$; optical-model analysis, deduced energy and target mass dependences of the potential; compared phenomenological results to those of microscopic models.

The results of cross-section measurements for the reactions ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},X)\mathrm{Au}$, $E=4.8\mathrm{} \mathrm{and} 25.2$ GeV and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)\mathrm{Au}$, $E=8.0\mathrm{}$ GeV are reported. The observed yields of the gold isotopes show a similar dependence on mass number for each reaction, differing slightly in the position of the centroid of the distribution. As the projectile energy increases, the inferred excitation energy of the primary residues remains the same or decreases slightly. This observation is in agreement with the predictions of the intranuclear cascade model of relativistic heavy ion collisions.

NUCLEAR REACTIONS ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},X)\mathrm{Au}$, $E=4.8,25.2$ GeV; ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},X)\mathrm{Au}$, $E=8.0\mathrm{}$ GeV; measured Au isotopic distributions, relativistic heavy ions, target fragmentation, Ge(Li) spectroscopy.

A spectroscopic investigation of yrast and near-yrast states in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$ and ${}_{}{}^{153}{}_{}{}^{}\mathrm{Er}$ is presented. We report measurements of prompt and delayed excitation functions, $\gamma -\gamma$ coincidences, isomeric lifetimes, and $\gamma$-ray angular distribution, obtained chiefly from the reactions ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},xn){}_{}{}^{152,153}{}_{}{}^{}\mathrm{Er}$ using carbon beams of laboratory energy 65-95 MeV. The levels observed extend to a spin of $J\ge \frac{43}{2}$ and include two long-lived isomers in ${}_{}{}^{153}{}_{}{}^{}\mathrm{Er}$. The nuclear structure is discussed in terms of the shell model and compared with the systematic behavior of levels in $N=84\mathrm{}$ and $N=85\mathrm{}$ isotones.

NUCLEAR REACTIONS ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},xn)$ $E=65\mathrm{}-95$ MeV; ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}({}_{}{}^{11}{}_{}{}^{}\mathrm{B},xn)$ $E=40\mathrm{}-70$ MeV; ${}_{}{}^{124}{}_{}{}^{}\mathrm{Te}({}_{}{}^{32}{}_{}{}^{}\mathrm{S},xn)$ $E=125\mathrm{}-155$ MeV. Measured $I_{\gamma }\mathrm{}(E,t)\mathrm{}$, $I_{\gamma }\left(\theta \right)$, $\gamma -\gamma \mathrm{}\left(t\right)\mathrm{}$. Deduced level sequences, $T_{\frac{1}{2}}$, $J^{\pi }$. Continuous and pulsed beams, enriched targets, Ge(Li) detectors, NaI(Tl) multiplicity filter.

The yields of several nuclides produced in the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ reaction have been measured over the range $E_{\mathrm{c}.\mathrm{m}}=16\mathrm{}-34$ MeV. The excitation function for the production of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ displays a regular sequence of narrow fine-structure resonances similar to those previously observed in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ reaction. This is the first time that such structure has been observed for systems of non-$\alpha$-particle nuclei. Intermediate-width resonances are observed in the yield of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ at $E_{\mathrm{c}.\mathrm{m}}=19.5,23.5,27.5, \mathrm{and} 31$ MeV. Correlated structure appears in the inelastic scattering cross section to the $3^{-}$ state of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ at all these energies, except possibly $E_{\mathrm{c}.\mathrm{m}}=19.5\mathrm{}$ MeV. The resemblance of the 23.5-MeV structure to anomalies previously observed in the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ reactions is noted, and some properties of the compound system are deduced.

NUCLEAR REACTIONS ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},x)$; $E_{\mathrm{c}.\mathrm{m}}=16\mathrm{}-34$ MeV; $\sigma$ total; correlated fine-structure and intermediate resonances discussed; properties of ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ deduced.

The ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$(${}_{}{}^6{}_{}{}^{}\mathrm{Li}$,${}_{}{}^6{}_{}{}^{}\mathrm{He}$)${}_{}{}^{54}{}_{}{}^{}\mathrm{Co}$ reaction was studied at an incident energy of 40 MeV. The results complement earlier (${}_{}{}^3{}_{}{}^{}\mathrm{He},t$) and ($p,n$) work. If one assumes approximate validity of one-step microscopic selection rules, and that the reaction strongly populates $\simeq {\left(1\mathrm{}{f}_{\frac{7}{2}}\right)}^{-2\mathrm{}}$ states, the results suggest the previously unspecified $3^{+}$, $5^{+}$, and $6^{+}$ states of this configuration lie at 2.285, 2.149, and either 3.085 or 3.128 MeV in ${}_{}{}^{54}{}_{}{}^{}\mathrm{Co}$, respectively.

NUCLEAR REACTIONS ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$(${}_{}{}^6{}_{}{}^{}\mathrm{Li}$,${}_{}{}^6{}_{}{}^{}\mathrm{He}$)${}_{}{}^{54}{}_{}{}^{}\mathrm{Co}$, $E=40\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$. DWBA analysis. ${}_{}{}^{54}{}_{}{}^{}\mathrm{Co}$ levels deduced.

Time-dependent Hartree-Fock computations are performed for the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ system at a laboratory bombarding energy of 204 MeV. We employ an approximation in which the components of the wave functions perpendicular to the reaction plane are held constant in time. At this energy the total reaction cross section is comprised of approximately equal amounts of fusion and deep inelastic scattering. Fusion is found for those entrance channel angular momenta between $l=31\mathrm{}\hslash$ and $l=75\mathrm{}\hslash$; strongly damped inelastic scattering is found above and below this region. The angular momentum excited in the inelastic fragments is shown to have a different character in the different inelastic branches and this behavior could conceivably be used as a test to experimentally prove or disprove the existence of the fusion window.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({}_{}{}^{93}{}_{}{}^{}\mathrm{Nb},x)$ in time-dependent Hartree-Fock approximation. Fusion and deep-inelastic scattering.

Fusion cross sections for the reaction pairs ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ (leading to ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$) and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ (leading to ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$) are examined to extract critical angular momenta. At low energies entrance channel effects are present, whereas at higher energies the results are qualitatively consistent with a common limiting angular momentum characteristic of the compound nucleus. Comparison with angular-momentum-dependent level densities suggests that the fusion cross sections at intermediate energy are sensitive to the availability of a sufficient level density in the compound nucleus. A model calculation employing the criterion that the level spacing of a particular angular momentum be comparable to or smaller than the level widths is used to calculate fusion cross sections. The results are in qualitative agreement with experiment, accounting for both the magnitude of the cross sections and the periodicity of the gross structure in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$.

NUCLEAR REACTIONS Heavy ion fusion cross sections; compound nuclear level density limitations.

It is shown how spin-orbit interactions affect resonant backward angular distributions of strongly absorbed particles.

NUCLEAR REACTIONS Heavy ions, backward angles, spin-orbit interactions, resonances.

Levels in ${}_{}{}^{106}{}_{}{}^{}\mathrm{Ag}$ have been studied using heavy-ion reactions. The experiments included $\gamma$-ray yields as a function of bombarding energy, $\gamma$-ray angular distributions, $\gamma$-ray linear polarizations, and three-detector $\gamma -\gamma$ coincidence measurements. The decay scheme includes four collective bands with low-lying bandheads. The energies, $\gamma$-ray mixing ratios, and branching ratios of states in these bands are shown to be in good agreement with the corresponding quantities calculated using a two-particles-plus-rotor model at a small, symmetric deformation ($\delta =0.12\mathrm{}$). The Coriolis and recoil effects are explicitly included and a variable moment of inertia is used. The calculation also shows that the four bands have predominant configurations $\nu \left(d_{\frac{5}{2}}\right)\otimes \pi \left(g_{\frac{9}{2}}\right)$, $\nu \left(g_{\frac{7}{2}}\right)\otimes \pi \left(g_{\frac{9}{2}}\right)$, $\nu \left(h_{\frac{11}{2}}\right)\otimes \pi \left(p_{\frac{1}{2}}\right)$, and $\nu \left(h_{\frac{11}{2}}\right)\otimes \pi \left(g_{\frac{9}{2}}\right)$, respectively. The $\Delta I=1\mathrm{}$ and $\Delta I=2\mathrm{}$ level sequences in the bands can be understood on the basis of the positions of the neutron and proton Fermi surfaces in the respective Nilsson bases. Another band observed experimentally on a ${10}^{-}$ bandhead at 2.4416 MeV is thought to have a four-quasiparticle structure.

NUCLEAR STRUCTURE ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}({}_{}{}^{14}{}_{}{}^{}\mathrm{N},4n){}_{}{}^{106}{}_{}{}^{}\mathrm{Ag}$ at 49 MeV: measured $I_{\gamma }\left[E\right({}_{}{}^{14}{}_{}{}^{}\mathrm{N}\left)\right]$, $I_{\gamma }\left(\theta \right)$, $P_{\gamma }$, $\gamma -\gamma$ coin., $\gamma -\gamma$ DCOQ. ${}_{}{}^{106}{}_{}{}^{}\mathrm{Ag}$ deduced levels, $J$, $\pi$, $\gamma$ mixing ratios. Two-particle-plus-rotor calculations, Coriolis. Calculated levels, mixing ratios, branching ratios, lifetimes. Ge(Li) detectors.

The fission decay of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ has been measured as a function of excitation energy in inelastic scattering of 120 MeV $\alpha$ particles. Total kinetic energies and masses of fission fragments were measured by the double energy method. It is observed that the total kinetic energy $E_K$ decreases and that the valley in the mass distribution is reduced when the excitation energy of the system is increased. No indication of anomalous total kinetic energy release in the region of the giant quadrupole resonance has been found. A qualitative interpretation of the data is given on the basis of a static scission point model.

NUCLEAR REACTIONS, FISSION ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}(\alpha ,{\alpha }^{\prime }f)$, $E=120\mathrm{}$ MeV, ${\theta }_{\alpha }=16\mathrm{}°$; measured total kinetic energy and fission fragment mass distributions as a function of excitation energy.

The ground-state spontaneous-fission half-lives of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$, and ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$ were redetermined using solutions of highly enriched uranium in spinner detectors. The following values were obtained: >2.7×${10}^{17}$ years for ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$; (1.42±0.08)×${10}^{16}$ years for ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$; (9.8±2.8)×${10}^{18}$ years for ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$; (2.43±0.13)×${10}^{16}$ years for ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$. The values for ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$ are in agreement with the systematics for spontaneous-fission half-lives of even-even nuclides. The spontaneous-fission of the odd-$A$ uranium isotopes 233 and 235 is considerably hindered (hindrance factors >1.3 and 3, respectively).

RADIOACTIVITY, FISSION ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$(sf), ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$(sf), ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$(sf), ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$(sf); measured $T_{\frac{1}{2}}$ of sf, spinner detector.