The $\beta -\gamma$ angular correlation in the decay of ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$ has been measured using a symmetric four detector system and an activated LiF target. ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$ was produced by the ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}(d, p){}_{}{}^{20}{}_{}{}^{}\mathrm{F}$ reaction using a low-energy deuteron beam ($E_d=2\mathrm{}$ MeV). Correlation data were acquired for ${\theta }_{\beta -\gamma }=90\mathrm{}°$ and ${\theta }_{\beta -\gamma }=180\mathrm{}°$ and these data were analyzed for systematic differences as a function of electron energy ($E_{\beta }$). We report a corrected first order slope to the ratio of $\beta$ spectra $\frac{N\left(180\mathrm{}°\right)}{N\left(90\mathrm{}°\right)}$ of (+0.5 ±0.7)${10}^{-3\mathrm{}}$ ${\mathrm{}\left(\mathrm{MeV}\right)\mathrm{}}^{-1\mathrm{}}$, with an intercept for this ratio of 1.001 ±0.002. Incorporating this value for the slope with other data on the $A=20\mathrm{}$ system, we find an upper limit for the second class current contribution to the correlation which is less than $\frac{1}{3}$ of the contribution of weak magnetism and consistent with zero.

RADIOACTIVITY ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$; measured $\beta -\gamma$ angular correlation. Determined induced weak currents.

The decay properties of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$ were investigated with the use of mass-separated sources. Singles and coincidence measurements were made by using x- and $\gamma$-ray Ge(Li) detectors as well as a Si(Li) electron detector. These results were combined with previously available conversion-electron data which had been obtained with a magnetic spectrometer. From this information a level scheme was constructed for ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$. A tentatively proposed level at 317 keV was eliminated on the basis of our results. In addition, several transitions attributed to ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$ decay were not observed in the present study. $\alpha$ particle and $\gamma$-ray spectra were also measured with the detectors positioned in calibrated geometries. The $\alpha$-decay energy and branching ratio of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$ were determined to be 3915±10 keV and (2.8±0.5)×${10}^{-7\mathrm{}}$, respectively.

RADIOACTIVITY ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$, measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ coin, $e\gamma$ coin, $E_{\alpha }$, $I_{\alpha }$; ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ deduced levels, $J^{\pi }$; ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$ deduced $\alpha$-decay branching ratio. Mass-separated sources.

The impact of second-forbidden corrections is studied in order to relate the $\frac{\epsilon }{{\beta }^{+}}$ ratio, the spectral shape factor, and the $\beta -\gamma$ directional correlation measurements in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$ decay.

RADIOACTIVITY ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$; second-forbidden corrections to $\beta$-decay calculations.

The ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}(t, p){}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ reaction has been studied with a 94% enriched ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$O target, a 17-MeV triton beam, and a multiangle magnetic spectrograph. Proton groups from the ($t, p$) reaction on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ in the target served for energy calibration. An average of data at four angles gives a $Q_0$ value of -4809 ± 15 keV, from which the mass excess of ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ is calculated to be 25,077.5 ± 15 keV. Excited states of ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ are found at 2089 ± 20, (2712 ± 20, tentative), 4559 ± 25, and 5703 ± 25 keV. The mass excess of ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$, plus earlier data for $A=12\mathrm{}$, $T=2\mathrm{}$, gives a value of $d=+2.8\mathrm{}\pm 8.6$ keV for the coefficient of the cubic term in the isobaric multiplet mass equation.

NUCLEAR STRUCTURE ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$: measured $Q$ values for proton groups in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}(t, p){}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ reaction; derived ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ mass excess, $E_{\mathrm{exc}}$ of ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ excited states, IMME coefficients.

A reported splitting of the lowest $T=2\mathrm{}$ strength in ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ has been confirmed by examining resonances in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\alpha , \gamma )$ ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ reaction at excitation energies in the region of 9.28-9.36 MeV. A level at 9298 ± 2 keV in ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ is found to have $\gamma$-decays to the 1+, $T=1\mathrm{}$ level at 7216 keV and to a $T=0\mathrm{}$ level at 3756 keV. The former transition is attributed to a $T=2\mathrm{}$ component in the 9298 keV level, with, however, the main $T=2\mathrm{}$ strength remaining in the level at 9338 ± 2 keV, as reported previously. Evidence is presented for a weak (9338→3756), $\Delta T=2\mathrm{}$ transition in addition to the dominant (9338→7216), $\Delta T=1\mathrm{}$ $\gamma$-decay branch. The two levels at 9298 and 9338 keV are interpreted as an isospin-mixed doublet. The perturbing matrix element is estimated to be 16 ± 3 keV, and the unperturbed $T=2\mathrm{}$ state to lie at 9330 ± 4 keV.

NUCLEAR STRUCTURE Splitting of lowest $T=2\mathrm{}$ level ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$; measured $\gamma$ decays, $\omega \gamma$ from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\alpha , \gamma )$; deduced transition strengths, isospin mixing.

Systematics are presented from our study of the Ge nuclei by means of the ($p, t$) reaction. From observed intensities and excitation energies, conclusions are drawn concerning structure and reaction mechanisms. They are discussed in the frame of microscopic calculations. These calculations predict a shape transition from a nearly spherical nucleus (${}_{}{}^{70}{}_{}{}^{}\mathrm{Ge}$) to a slightly oblate one (${}_{}{}^{74}{}_{}{}^{}\mathrm{Ge}$). The energies of the low-lying 0+ levels are well fitted; dynamical effects induced by pairing fluctuations are shown to play a major role in this feature as well as in the striking evolution of their intensitie in the ($p, t$) reaction. A connection is presented with the possibility of 0+ pairing isomer states. The outstanding splitting of the $L=3\mathrm{}$ strength at $N=42\mathrm{}$ appears as a characteristic feature of this region suggesting coupling effects in octupole modes.

NUCLEAR REACTIONS ${}_{}{}^{70,72,74,76}{}_{}{}^{}\mathrm{Ge}(p, t)$, deduced and presented systematics about nuclear structure and reaction mechanisms.

NUCLEAR STRUCTURE ${}_{}{}^{70,72,74,78}{}_{}{}^{}\mathrm{Ge}$; calculated deformation energy curves and collective spectra. Used microscopic theory. Compared with experimental systematics.

The properties of the nuclear states up to $J=\frac{23}{2^{-}}$ are investigated in odd-$A$ scandium isotopes ${}_{}{}^{45,47}{}_{}{}^{}\mathrm{Sc}$. The investigations are carried out in the framework of Hartree-Fock projection formalism by employing a realistic nucleon-nucleon interaction. An inert ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ core is assumed and all the valence nucleons are explicitly treated in the configuration space of the full $\mathrm{pf}$ shell. The energy levels, static electromagnetic moments and the electromagnetic transition probabilities are evaluated from the band-mixing calculations wherein the lowest four energetically close intrinsic states of the nuclei are taken into account. The theoretical results are in fair agreement with the available experimental data.

NUCLEAR STRUCTURE Scandium isotopes: calculated energy levels, static moments, $B\left(E2\mathrm{}\right)\mathrm{}$ and $B\left(M1\mathrm{}\right)\mathrm{}$. Hartree-Fock projection formalism with band mixing.

A tensor plus central potential is used to explore the universality of the effective interactions for $N=28, 50, \mathrm{and} 82$ isotones. It is found that the central components of the potential can be practically unified for the three mass regions. The tensor components are different for the three mass regions with the tendency of lesser importance for heavier nuclei. The energy spectra of the low-lying states of $N=28, 50, \mathrm{and} 82$ isotones are calculated and compared with experimental data.

NUCLEAR STRUCTURE $N=28, 50, \mathrm{and} 82$, calculated effective interactions and energy spectra.

The odd-$A$ Ru isotopes with $A=101-105\mathrm{}$ are studied in a semimicroscopic model which couples the neutron quasiparticle motion in the $N=50-82\mathrm{}$ shell to the quadrupole vibrations of the neighbouring Ru core. The agreement between the calculated and available experimental data on energy spectra, spectroscopic factors, moments and transition rates is found to be reasonably good.

NUCLEAR STRUCTURE ${}_{}{}^{101,103,105}{}_{}{}^{}\mathrm{Ru}$; calculated levels, $J$, $\pi$, $S$, $Q$, $\mu$, $B\left(E2\mathrm{}\right)\mathrm{}$, $B\left(M1\mathrm{}\right)\mathrm{}$, quasiparticle-phonon coupling.

The fireball model of relativistic heavy-ion collision uses chemical equilibrium relations to predict cross sections for particle and composite productions. These relations are examined in a canonical ensemble model where chemical equilibrium is not explicitly invoked.

NUCLEAR REACTIONS Fireball; particle production; relativistic heavy ions; chemical equilibrium.

The properties of the $1^{-}$, $T=1\mathrm{}$ state of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ at 11278±4 keV excitation were studied by means of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha , \gamma ){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ reaction. The level parameters determined for this state are not in complete agreement with those reported in a recent study. The implication of this discrepancy for the feasibility of a measurement of parity nonconservation in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ is discussed.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha , \gamma ){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, $E=8.18\mathrm{}$ MeV; measured $E_{\gamma }$, $I\left({\ominus }_{\gamma }\right)$; ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ resonance deduced excitation energy, $J$, $\pi$, $\omega {\gamma }_0$, $T$. Natural targets. Ge(Li) and NaI(Tl) detectors.

The total fusion cross section for the sytem ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ has been measured in the energy region between $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=14\mathrm{}$ MeV and 33 MeV. A maximum fusion cross section of 1200±50 mb was obtained in good agreement with the results for other systems in this mass range.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$, $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=14-33\mathrm{}$ MeV; measured ${\sigma }_{\mathrm{fusion}}$.

A technique is described for obtaining the partial-wave analysis of elastic scattering of pions from a spin-zero nucleus. Unitarity is not imposed as a mathematical constraint, so that the system of equations to be solved is relatively simple. As an illustration, the method is applied to ${\pi }^{+}$-${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ elastic scattering at 50 MeV.

NUCLEAR REACTIONS phase shift analysis, elastic scattering, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({\pi }^{+}, {\pi }^{+})$.

Complete analog dominance in the nucleon charge exchange transitions affecting ratios of ($\pi , \pi N$) cross sections near the (3,3) resonance is experimentally unfounded. No dramatic jumps with neutron number in neutron removal ratios are now expected. There may be a vestige of analog dominance in the deviation of $\frac{\sigma ({\pi }^{+}, {\pi }^{+}p)}{\sigma \left({\pi }^{+}{\pi }^{0}p\right)}$ from the impulse approximation. Disagreement of an intranuclear cascade calculation with the nucleon charge exchange model (and experiment) is also discussed.

NUCLEAR REACTIONS $\sigma (\pi , \pi N)$ ratios, $T_{\pi }$ near 180 MeV: analog and nonanalog nucleon charge exchange; ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, and emulsion targets; intranuclear cascade model discrepancy.

Giant resonance spectra for ${}_{}{}^{144,154}{}_{}{}^{}\mathrm{Sm}$ obtained by 67-MeV ($p, p^{\prime }$) measurements have been reanalyzed and compared with distorted-wave Born approximation calculations. The calculations use a more recent isovector interaction potential and a modified description of the giant dipole resonance as well as predictions for the splitting of giant resonances in deformed nuclei. The data are shown to be consistent with excitation of isoscalar 0+ and 2+ and isovector $1^{-}$ resonances which deplete nearly 100% of their respective energy-weighted sum rules.

NUCLEAR REACTIONS ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}(p, p\text{'})$; $E_p=67\mathrm{}$ MeV; measured $\sigma (E_x, \theta )$. Discuss giant monopole, dipole, quadrupole resonances; deduced $L$, ${\beta }_L$.

Differential cross sections for the elastic scattering of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at 158.2 MeV are presented. These data along with data from lower energies are analyzed within the framework of an optical-model potential.

NUCLEAR REACTIONS ${}_{}{}^4{}_{}{}^{}\mathrm{He}(\alpha , \alpha )$, $E_{\alpha }=158.2\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, $\theta =10\mathrm{}°-94\mathrm{}°$ c.m.; optical model analysis.

Amado's arguments concerning minimal requirements of unitarity and analyticity are used to derive an effective interaction in a nonrelativistic three-body model of nucleon-nucleon scattering. It is shown that the nonlocal effective interaction between two heavy particles, generated by the exchange of a light particle which may bind to either heavy with binding energy equal to its rest mass reduces in the adiabatic limit to a local Yukawa interaction with range and strength determined by the mass of the transferred particle. The result is independent of perturbation theory or field-theoretical arguments.

NUCLEAR REACTIONS Three-body model of nucleon-nucleon scattering, equivalent potential from minimal unitarity and analyticity constraints.

Increased use of the ${}_{}{}^{82}{}_{}{}^{}\mathrm{Sr}$-${}_{}{}^{82}{}_{}{}^{}\mathrm{Rb}$ positron generator in nuclear medicine has led to a redetermination of the half-lives of the isotopic components of this system. The half-life of ${}_{}{}^{82}{}_{}{}^{}\mathrm{Sr}$ was measured to be 25.55±0.15 days and that of ${}_{}{}^{82}{}_{}{}^{}\mathrm{Rb}$ 1.273±0.002 min.

RADIOACTIVITY ${}_{}{}^{82}{}_{}{}^{}\mathrm{Sr}$ and ${}_{}{}^{82}{}_{}{}^{}\mathrm{Rb}$: measured $T_{\frac{1}{2}}$.

The static quadrupole moment of the first 2+ excited state of ${}_{}{}^{74}{}_{}{}^{}\mathrm{Se}$ was measured by using the reorientation effect in Coulomb excitation. The measurements yielded for constructive interference via the second 2+ excited state $Q_{2+}=-0.36\mathrm{}\pm 0.07e$ b. This value gives a direct evidence of a prolate nuclear deformation for $N=40\mathrm{}$ in the even-$A$ selenium isotopes.

NUCLEAR REACTIONS ${}_{}{}^{74}{}_{}{}^{}\mathrm{Se}(\alpha , {\alpha }^{\prime })$, $E=7.3\mathrm{}$ MeV; ${}_{}{}^{74}{}_{}{}^{}\mathrm{Se}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$′), $E=33, 34$ MeV; measured Coulomb excitation ${}_{}{}^{74}{}_{}{}^{}\mathrm{Se}$ deduced ${Q_2}^{+}$, $B(E2; 0^{+}\to 2^{+})$. Enriched targets.

Nuclear matter overlap integrals between two nuclei are calculated for density distributions generated by folding a short range function over arbitrarily shaped sharp surfaces of the two nuclei. Explicit formulas are derived for two choices of the folding function, viz., a Gaussian and a Yukawa function. An approximation scheme is given to facilitate a quick evaluation of the overlap integrals and is found to give results which are in good agreement with the exact results over a wide range of masses and spheroidal deformations of the two nuclei.

NUCLEAR REACTIONS, Heavy-ion reactions, fission. Calculation of overlap integrals between arbitrarily shaped diffuse surface nuclei, Yukawa and Gaussian folding functions, approximation scheme for spheroidal nuclei, comparison of exact and approximate results.