The energy distributions of protons from the ($e,e^{\prime }p$) reaction on $N=82\mathrm{}$ nuclei with even $Z$ have been measured. The cross sections of the ($\gamma ,p_0+p_1$) reaction have been estimated. Two prominent isobaric analogs have been found in each nucleus. The results were used for the systematic discussion of the odd-odd parent nuclei ${}_{}{}^{138}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$, ${}_{}{}^{142}{}_{}{}^{}\mathrm{Pr}$, and ${}_{}{}^{144}{}_{}{}^{}\mathrm{Pm}$. The $1^{-}$ states are estimated at 600 and ∼2500 keV for ${}_{}{}^{138}{}_{}{}^{}\mathrm{Cs}$, 500 and 3000 keV for ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$, 1100 and 3700 keV for ${}_{}{}^{142}{}_{}{}^{}\mathrm{Pr}$, and 1400 and 4300 keV for ${}_{}{}^{144}{}_{}{}^{}\mathrm{Pm}$. The parameters of these states are discussed in terms of a quasiproton and single-neutron model.

Two new $\alpha$-emitting isotopes of element 105 with mass numbers 261 and 262 have been discovered. The 8.93-MeV 1.8-sec ${}_{}{}^{261}{}_{}{}^{}\mathrm{Ha}$ was produced by the reactions ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cf}({}_{}{}^{15}{}_{}{}^{}\mathrm{N},4n){}_{}{}^{261}{}_{}{}^{}\mathrm{Ha}$ and ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},4n){}_{}{}^{261}{}_{}{}^{}\mathrm{Ha}$, and the 8.45-MeV 40-sec ${}_{}{}^{262}{}_{}{}^{}\mathrm{Ha}$ by the reaction ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}({}_{}{}^{18}{}_{}{}^{}\mathrm{O},5n){}_{}{}^{262}{}_{}{}^{}\mathrm{Ha}$. The isotopic assignments are based on both $\alpha$-recoil milking and mother-daughter time-correlation measurements. An upper limit of 50% for branching by spontaneous fission was set for ${}_{}{}^{261}{}_{}{}^{}\mathrm{Ha}$. A so far unassigned 25-sec spontaneous-fission activity was observed in the bombardment of ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$ with ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions.

A clean separation is made between the compound-nucleus and direct-reaction contributions to the low-energy continuum region of the energy spectra of protons from inelastic scattering. Bombarding energies are 12 and 17 MeV, and target nuclei are the isotopes of Ni, Zr, Cd, Mo, and Sn. The compound-nucleus contribution is studied by determining level-density parameters and the proton-to-neutron-emission ratios. These are in good agreement with predictions from statistical theory.

The ($d,n$) reaction on ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$, and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Mo}$ has been studied at 12-MeV deuteron bombarding energy using the neutron time-of-flight technique with an over-all neutron time resolution of 1.9 nsec. Angular distributions of neutron groups leading to states in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Tc}$, ${}_{}{}^{95}{}_{}{}^{}\mathrm{Tc}$, and ${}_{}{}^{97}{}_{}{}^{}\mathrm{Tc}$ were measured in the angular range between 15 and 70°. The measured cross sections are analyzed in the framework of the distorted-wave theory of stripping reactions to deduce the $l$ values and proton spectroscopic factors of the states in the residual nuclei. The results are compared with the corresponding data available from (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) studies. Arguments based on the shell-model theory have been used to make tentative spin assignments. The fractionation of the single-particle states and their centroid energies are determined. Tentative ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$, and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Mo}$ ground-state configurations are deduced from the analysis.

In-beam $\gamma$-ray measurements of the excited states in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$ have been made using the reaction ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}(p,n\gamma ){}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$ at incident proton energies between 3.0 and 6.3 MeV. Singles, threshold, and $\gamma -\gamma$ coincidence measurements were made using Ge(Li) detectors and an on-line two-parameter data acquisition system. By these methods more than 70 $\gamma$ rays associated with the deexcitation of levels in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$ have been observed. $\gamma -\gamma$ coincidence spectra produced by gates on 12 of the stronger transitions were used along with a threshold experiment to identify 43 levels with energies up to 4.3-MeV excitation. 12 of these levels having energies of 1984, 2326, 2331, 2992, 3066, 3126, 3179, 3274, 3328, 3434, 3462, and 3636 keV had not been previously reported. Branching ratios are given along with a decay scheme for ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$.

New determinations of the half-lives of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ have been made. Improved techniques have allowed the half-life values to be measured with greater accuracy than has been heretofore achieved. Samples were prepared by molecular plating and counted in a intermediate-geometry $\alpha$-proportional counter with an extremely flat pulse-height plateau. The small amount of residual nonplated uranium was counted in a $2\pi$ counter. Energy analysis with a silicon-junction detector was used to measure the presence of "foreign" activities. For ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$, the measured specific activity was (4798.1±3.3) (dis/min)/(mg ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$), corresponding to a half-life of (7.0381±0.0048) × ${10}^8$ yr. For ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, the specific activity was measured as (746.19±0.41) (dis/min)/(mg ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$), corresponding to a half-life of (4.4683±0.0024) × ${10}^9$ yr. Errors quoted are statistical (standard error of the mean), based upon the observed scatter of the data. This scatter exceeds that expected from counting statistics alone. We believe that systematic errors, if present, will no more than double the quoted errors.

The parity-violating forward-backward asymmetry of the 501-keV $\gamma$ radiation emitted by ${}_{}{}^{180m}{}_{}{}^{}\mathrm{Hf}$ polarized at low temperatures is measured to be -(1.66±0.18)% at a polarization of 72%. From this asymmetry the magnitude of the irregular $\frac{\tilde{E}2}{M2\mathrm{}}$ mixing ratio is deduced to be 0.038±0.004, in good agreement with results of circular polarization measurements. The regular $\frac{E3\mathrm{}}{M2\mathrm{}}$ multipole mixing ratio of the 501-keV $\gamma$ ray is deduced to be 5.3±0.3, in agreement with results of directional-correlation measurements. The hyperfine splitting energy of ${}_{}{}^{180m}{}_{}{}^{}\mathrm{Hf}$ introduced as an impurity in Zr${\mathrm{Fe}}_2$ is deduced to be -(7.9±0.5) mK.

A new technique is presented for determining mass and charge distribution in fission. This method is based on obtaining the independent yields of the even-even fission products from the measured intensities of $2^{+}\to 0^{+}$ ground-state band transitions deexciting the prompt-fission products. Transition intensities for members of ground-state bands in 36 even-even fission-product nuclei have been used to determine the centroids ($Z_p$) and widths (${\sigma }_Z$) of the charge distribution for eight chains of fission products with constant mass and also to determine the centroids ($Z_A$), widths (${\sigma }_A$), and yields ($Y_Z$) of the mass distribution for 12 chains of fission products with constant charge. The method has been applied to analyze the charge and mass distributions of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ spontaneous fission. The results when compared with the standard radiochemical and $K$ x-ray technique give satisfactory agreement. The discrepancies which exist are predominantly associated with regions influenced strongly by nuclear shells. Examples are given relating the observed ground-state band transition intensities with other observed fission variables such as kinetic energy release and neutron-evaporation systematics.

Low-energy $\gamma$ rays, in the range from 45 to 230 keV, following the spontaneous fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$, are observed with a high-resolution Ge(Li) detector [full width at half maximum (FWHM) 500 eV at 81 keV], in coincidence with $K$ x rays from the fission fragments, observed with a Si(Li) detector (FWHM 350 eV at 31 keV). Sixteen 1024-channel $\gamma$-ray spectra were accumulated and sorted by computer, corresponding to windows set on $K$ x rays from Y, Zr, Nb, Mo, Tc Ru, Rh, Pd, Pr, Ce, La, Ba, Cs, Xe, I, and Sb. In conjunction with previous works, these data allowed both mass and charge assignments to be made for a number of the observed $\gamma$-ray transitions.

Measurement of the angular distribution of the 363-keV $\gamma$ radiation following the decay of ${}_{}{}^{159}{}_{}{}^{}\mathrm{Gd}$ oriented in Gd${\mathrm{Fe}}_2$ at low temperatures has yielded a vanishing value of the parity-non-conserving forward-backward asymmetry, indicating in this transition no large effect resulting from the parity-violating weak nucleon-nucleon interaction. Vanishing asymmetries were observed for other strongly hindered transitions in ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}$ and in ${}_{}{}^{161}{}_{}{}^{}\mathrm{Dy}$. The 0-90° anisotropy of the 363-keV angular distribution has yielded a value for the magnetic moment of the ${}_{}{}^{159}{}_{}{}^{}\mathrm{Gd}$ ground state of $\mu =(-0.44\mathrm{}\pm 0.03){\mu }_N$. The magnitude of the hyperfine field of Tb in Gd${\mathrm{Fe}}_2$ has been estimated to be 370 ± 80 kG, based on observation of the 0-90° anisotropy of $\gamma$ transitions in ${}_{}{}^{161}{}_{}{}^{}\mathrm{Dy}$. The multipole characters of various $\beta$ and $\gamma$ transitions following the decay of oriented ${}_{}{}^{153,159}{}_{}{}^{}\mathrm{Gd}$ and ${}_{}{}^{161}{}_{}{}^{}\mathrm{Tb}$ have been deduced.

A two-parameter coincident (x-ray-x-ray) measurement was made using a Si(Li) x-ray detector and a Ge(Li) x-ray detector to study the x-ray production in the ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ fission process. $K$ x-ray peaks from adjacent $Z$ fission products are well resolved in both detectors. The measurement yields the result that there is a large number of coincident events with x rays from the same $Z$ element as well as with x rays from the complementary fission product (e.g., Cs $K$ x rays are in coincidence with both the complementary Tc $K$ x rays and the Cs $K$ x rays). The various possibilities one may consider are: (1) $K$ x-ray production by the primary fission process followed by internal conversion, (2) multiple $K$ x-ray production in the stopping process of the fission products, (3) $K$-shell ionization resulting from $\beta$ decay of the fission fragments followed by internal conversion in the same fragment, and (4) multiple internal-conversion processes from cascading transitions. Each of these four possible causes for self-coincident x-ray production is explored.

Quasifree $p-p$ scattering has been studied in the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}\mathrm{}(p,2p)n$ between 21.5 and 56.4 MeV. Results have been fitted with simple impulse-approximation models which reproduce the position and shape of the quasifree peak but give too high an absolute value for the cross section.

The differential cross section for the reaction ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}(d,{}_{}{}^6{}_{}{}^{}\mathrm{Li}){}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ at 27.2 MeV, leading to the lowest $0^{+}$ and $2^{+}$ states was measured. The angular distributions show a diffraction pattern and forward peaking characteristic of a direct process. A distorted-wave Born-approximation (DWBA) calculation, in the zero-range approximation, with states represented by radial wave functions with $N=5\mathrm{}$ and $N=4\mathrm{}$ nodes for $L=0\mathrm{}$ and $L=2\mathrm{}$, respectively, was performed. The form factors correspond to the wave function of an $\alpha$ particle moving in a Woods-Saxon potential. From the optical-model analysis the relative strength of the $0^{+}$ and $2^{+}$ states can be determined within 20% error. In addition, a DWBA calculation including structure factors obtained on the basis of the pairing-plus-quadrupole model, with a coherent sum over the center-of-mass radial quantum number $N$, was used. The predicted ratio $\frac{\sigma \left(2^{+}\right)}{\sigma \left(0^{+}\right)}$ is 0.8 of the experimental value, with no significant difference in the shape of the angular distributions in both analyses.

Evidence for anomalous $g_l$ factors of the nucleons over the whole mass region is presented. The analysis has yielded $g_l^{\mathrm{e}\mathrm{f}\mathrm{f}}\mathrm{}\left(p\right)=1.09\mathrm{}\pm 0.03$ and $g_l^{\mathrm{e}\mathrm{f}\mathrm{f}}\mathrm{}\left(n\right)=-0.06\mathrm{}\pm 0.04$, which are compatible with the effect of the mesonic-exchange current.

The increase of the depth of nuclear potential wells and of the nucleon-nucleon attraction upon compression of nuclear matter is estimated.

A simple model calculation is presented where particle-hole and surface excitations are coupled. An application to the case of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ is presented in detail.

A simple model based on summing neutron-transfer diagrams is developed. This model gives a broad peak in the backward ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ elastic scattering cross section having some of the observed characteristics.