The level structures of ${}_{}{}^{79,81,83}{}_{}{}^{}\mathrm{Kr}$ have been investigated via the ($d, p$) stripping reaction using isotopically enriched gas targets at an incident deuteron energy of 11 MeV. Proton groups leading to about 14 states with excitation energies up to approximately 3 MeV have been identified in each of the above nuclei. Differential cross sections were measured from 20° to 160°, and were fitted with zero-range distorted-wave-Born-approximation calculations. Excitation energies, $l$ values, spectroscopic factors, and the implied values of $J^{\pi }$ are given. Comparisons are made with states in the selenium and germanium isotopes having the same number of neutrons and, respectively, one and two protons less than the krypton isotopes. Comparisons are also made between the present work and studies of ${}_{}{}^{79}{}_{}{}^{}\mathrm{Kr}$ via ${}_{}{}^{79}{}_{}{}^{}\mathrm{Rb}$ decay measurements. Two unresolved discrepancies are found between the two sets of measurements.

NUCLEAR REACTIONS ${}_{}{}^{78,80,82}{}_{}{}^{}\mathrm{Kr}(d, p){}_{}{}^{79,81,83}{}_{}{}^{}\mathrm{Kr}$, $E=11.0\mathrm{}$ MeV, measured $\sigma \left(\theta \right)$ and level energies; deduced $l$, $S$ with DWBA analysis.

The giant resonance regions of ${}_{}{}^{144,154}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been investigated by inelastic scattering of 80-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ions. The shapes of the resonance structure were observed to be quite similar for each target studied here. Comparison of the experimental cross sections with energy-weighted sum rules implies that the observed structure is probably comprised of more than just an isoscalar $E2\mathrm{}$ excitation.

NUCLEAR REACTIONS ${}_{}{}^{144,154}{}_{}{}^{}\mathrm{Sm}$ ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$'), $E_{{}_{}{}^3{}_{}{}^{}\mathrm{He}}\approx 80$ MeV, $E_x=0-40\mathrm{}$ MeV; measured $\sigma (E_x, \theta )$; discuss giant resonances.

Recoil ranges of 10 fission products in aluminum from the reactor neutron fission of ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$ were determined using radiochemical and $\gamma$-ray spectrometric methods. The recoil ranges were converted into kinetic energies of the fission fragments using different range-energy relations after applying necessary corrections for neutron evaporation. From the kinetic energy distribution, the kinetic energy deficit and average total kinetic energy released were obtained. Using the experimental kinetic energy data of a number of fissioning systems, the deformations of fission fragments for a given mass number were calculated to examine their dependence on the mass and charge of the fissioning nucleus. It was observed that for the asymmetric mass divisions the fragment deformation does not change appreciably with the fissionability parameter, while in the case of the symmetric mass division the deformation increases with the increase in the fissionability parameter. This difference is attributed to the influence of shells on the deformability of fission fragments.

The recoil properties of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Mg}$ formed by the interaction of protons of énergy 3.0-300 GeV with targets of gold and uranium have been measured by a thick-target technique. $\gamma$-ray spectroscopy without chemical separation was used to measure the nuclides of interest. The forward-to-backward ratio ($\frac{F}{B}$) of both nuclides from both targets exhibits a maximum near 3 GeV, decreasing from a value of about 2.0 at that energy to about 1.3 at 300 GeV. This behavior is strikingly similar to that of several neutron-deficient medium-mass nuclides formed from uranium, such as ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$, and seems to indicate that both types of products are formed in similar processes. The mean ranges of the light nuclides were found to decrease by about 25% from 3 to 300 GeV, also similar to the behavior of the neutron deficient products, although smaller in magnitude.

NUCLEAR REACTIONS ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ ($p$, fragmentation) ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Mg}$, $E=3-300\mathrm{}$ GeV; measured thick-target recoil properties.

A classical model with nuclear stretching under the influence of a repulsive conservative force and a dissipative radial force is proposed to explain the observed kinetic energy spectra and angular distributions of very heavy-ion reactions. The model is applied to the strongly damped collisions in the ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ + ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ reaction.

NUCLEAR REACTIONS Classical model with dissipative forces for very heavy ions.

A careful remeasurement of the ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}(n, \gamma )$ cross section using the pulse height weighting technique in small scintillators has been completed. The 4.9 eV resonance was used for calibration and the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(n, \alpha )$ cross section for flux shape. Estimated errors range from 1.4% near 30 keV to 3.3% at 550 keV. Individual resonance parameters were deduced in the 2.6-4.9 keV range and the fluctuations over 10's of resonances were analyzed below 90 keV. The fluctuations are larger than expected, limiting the precision attainable with monoenergetic sources using this standard. The fluctuation intensity appears to indicate intermediate resonance structure in the compound nucleus with ∼10 keV width and ∼40 keV spacing.

NUCLEAR REACTIONS ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}(n, \gamma )$, $E=3-550\mathrm{}$ keV; measured $\sigma \mathrm{}\left(E\right)\mathrm{}$; deduced ${}_{}{}^{198}{}_{}{}^{}\mathrm{Au}$ level parameters, strength functions, spacings.

Energy spectra at 90° in the laboratory were obtained for He, Li, Be, and B fragments from a uranium target irradiated with 4.9 GeV protons and 2.1 GeV/nucleon deuterons and $\alpha$ particles. Data at 25 and 155° were also obtained with the proton and $\alpha$ particle beams. In comparing the incident deuteron data with the incident proton data, it was found that the cross sections were a factor of 1.5 higher but the shapes of the energy spectra were unchanged. However, with incident $\alpha$ particles it was found that the cross sections were a factor of 3 to 4 larger, and the energy spectra were somewhat broadened indicating that the effective Coulomb barriers are 15% lower, and the apparent temperatures 1.5 MeV higher. It is concluded that in the $\alpha$ particle irradiations the deposition energies are larger than with either incident protons or incident deuterons.

NUCLEAR REACTIONS $\mathrm{U}(p, x)$, $E=4.9\mathrm{}$ GeV; $\mathrm{U}(\alpha , x)$, $E=2.1\mathrm{}$ GeV/nucleon; ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ measured $E_x$ at 90°, $\sigma \left(\theta \right)$, $\sigma$; ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ estimated $\sigma$. $\mathrm{U}(d, x)$, $E=2.1\mathrm{}$ GeV/nucleon; ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ measured $E_x$ at 90°, estimated $\sigma$; ${}_{}{}^6{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ estimated $\sigma$.

Using a thin film detector to indicate nuclear charge $Z$ from measured specific luminescence values, direct evidence was obtained for fragment nulcear charge structure in the thermal neutron induced fission of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$. The structure, occuring as a preference for formation of alternate $Z$ charge units, is most pronounced for fission events leading to higher total kinetic energy release.

NUCLEAR REACTIONS, FISSION ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}(n, f)$, $E=\mathrm{thermal}$; measured coin thin-film detector (TFD) luminescence, $E$ and $V$ of ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$* single fragments; deduced $Z$ fine structure in $E$ and $M$ distributions; confirmed heavy mass even-even periodicity at higher energies.

The ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}(d, {}_{}{}^3{}_{}{}^{}\mathrm{He}){}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ reaction was studied at a bombarding energy of 28 MeV. All known low-lying negative-parity states were observed; positive-parity states were either weak or absent. A new negative-parity state is suggested near 1.03 MeV. Distorted-wave calculations were made in order to extract spectroscopic factors. Much mixing of $l=1\mathrm{}$ and $l=3\mathrm{}$ transfers is observed. Detailed comparisons are made with wave functions proposed by Kolata et al. Somewhat larger configuration mixing is found, in keeping with known effects of $g_{\frac{9}{2}}$ neutron holes on $p_{\frac{3}{2}}$ and $f_{\frac{5}{2}}$ protons.

NUCLEAR REACTIONS ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}(d, d)$, $E=28\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, $\theta =12-71\mathrm{}°$, $\Delta \theta =1-2\mathrm{}°$. ${}_{}{}^{87}{}_{}{}^{}\mathrm{Sr}(d, {}_{}{}^3{}_{}{}^{}\mathrm{He})$, $E=28\mathrm{}$ MeV; measured $\sigma (E, \theta )$; $\theta =8-45\mathrm{}°$, $\Delta \theta =2-5\mathrm{}°$; enriched target, resolution 35 keV, DWBA analysis; ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ deduced levels, $S$.

A perturbation theory treatment is made of core-polarization effects in electromagnetic and inelastic scattering transitions due to high-lying collective excitations. Formulas are presented which make the connection between core-polarization parameters in inelastic scattering and effective charges from electromagnetic transitions. These relationships show that there is a natural disparity in neutron and proton polarizations, which arises from the departure (due to the neutron excess) of these high-lying collective excitations from pure isoscalar or isovector character. The resulting isospin-polarization matrix is calculated both from a schematic model and by making a connection with Bohr-Mottelson parametrization of isoscalar and isovector effective charges. The effects of spreading of the isoscalar giant resonance are taken into account in an approximate way which results in a formulation with one parameter free to be determined from empirical electromagnetic effective charges. Numerical results which show the effects of core polarization in electromagnetic transitions, ($\alpha , {\alpha }^{\prime }$), ($p, p^{\prime }$), and ($n, n^{\prime }$) are presented for ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ and ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$.

NUCLEAR REACTIONS Inelastic scattering of $\alpha$, $p$, $n$ on ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$, core polarization effect calculated from electromagnetic effective charges as examples of method developed.

Previous measurements of the $e\gamma$ double decay of ${}_{}{}^{113}{}_{}{}^{}\mathrm{In}$ at 35° have been extended to relative angles of emission of 15, 30, 45, 60, 90, 120, and 150°. The energy distributions of photons have been determined at each angle in the range from 30 to 210 keV and from 35 to 197 keV for $K\gamma$ and $\mathrm{}(L+M+N)\mathrm{}\gamma$ decays, respectively. The data are in agreement with the theory of the internal Compton effect of Spruch and Goertzel and the theory of radiation losses in internal conversion of Baumann and Robl. The maximum of the transition probability has been found at (39.8 ± 2.2)°, while that predicted by the theories is at 34.6°. The calculations have also been performed using the theory of "nuclear" $e\gamma$ double decay of Grechukhin. It has been shown that the contributions of this mechanism to the observed results are negligible. The integral coefficients obtained are $B_{K\gamma }=(1.11\mathrm{}\pm 0.04)\times {10}^{-3\mathrm{}}$ for photons in the energy range from 35 to 105 keV and $B_{\mathrm{}(L+M-N)\mathrm{}\gamma }=(1.01\mathrm{}\pm 0.08)\times {10}^{-3\mathrm{}}$ for photons in the energy range from 42 to 105 keV.

RADIOACTIVITY ${}_{}{}^{113}{}_{}{}^{}\mathrm{In}_{}^m{}_{}{}^{}$; measured $e\gamma$ double decay at 15, 30, 35, 45, 60, 90, 120, and 150°; deduced photon energy distributions in the range 30 to 210 keV for $K\gamma$ decay and 35 to 197 keV for $\mathrm{}(L+M+N)\mathrm{}\gamma$ decay; deduced angular distribution for photons of an energy of 35 to 105 keV for $K\gamma$ decay and 42 to 105 keV for $\mathrm{}(L+M+N)\mathrm{}\gamma$ decay; deduced integral energy distribution and integral $e\gamma$-double-decay coefficients.

High-resolution Ge(Li) detectors have been used to observe $\gamma$-ray singles and coincidence spectra of 30-h $\frac{11}{2^{-}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ and of 25-min $\frac{3}{2^{+}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$. Sources were produced by neutron irradiation of enriched ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$ metal, and, in the case of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$, were chemically purified to remove the ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ daughter. A total of 190 and 80 $\gamma$ rays are attributed to the decays of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ and ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$, respectively; and 174 and 77 of these transitions have been placed in a ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ level scheme involving 52 excited states. The $\beta$ feeding from the $\frac{11}{2^{-}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ to the $\frac{7}{2^{+}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ ground state was determined to be (5.2 ± 3.0)% ($log{f}_{1}t=10.5\mathrm{}$). The isomeric transition branch of $\frac{11}{2^{-}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$ to $\frac{3}{2^{+}}$ ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ was determined to be (22.2 ± 1.6)%. The 6-nsec isomer in ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ at 1797 keV has been assigned as $\frac{15}{2^{-}}$ and interpreted as a $\pi {\nu }_1{\nu }_2$ three quasiparticle state. The level structure of ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ is interpreted in terms of the shell model and core excitation considerations.

RADIOACTIVITY ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^m{}_{}{}^{}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Te}_{}^g{}_{}{}^{}$ [from ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$ ($n, \gamma$)]; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coin; deduced $log\mathrm{ft}$, IT branch. ${}_{}{}^{131}{}_{}{}^{}\mathrm{I}$ deduced levels, $J$, $\pi$. Enriched target; Ge(Li) detectors.

The electron shakeoff probabilities accompanying the internal conversion process have been calculated in the sudden approximation, using screened relativistic hydrogenic wave functions. The screening constants have been determined from the relativistic self-consistent-field calculations and the presence of a vacancy resulting from internal conversion has been taken into account. The present results indicate that relativistic effects cause an appreciable increase in the probabilities. It is also shown that the prediction of Carlson et al. is a good approximation to the shakeoff probability accompanying internal conversion. The calculated results have been compared with available experimental data. There is fairly good agreement between the calculated and the recently measured values. The need for new data is emphasized.

RADIOACTIVITY ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{109}{}_{}{}^{}\mathrm{Ag}$, ${}_{}{}^{113,114}{}_{}{}^{}\mathrm{In}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Xe}$, ${}_{}{}^{137}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{141}{}_{}{}^{}\mathrm{Pr}$, ${}_{}{}^{150}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{203}{}_{}{}^{}\mathrm{Tl}$; calculated shakeoff probability accompanying internal conversion.

Angular correlations of the 277.4-210.5 keV and the 371.9-277.4 keV $\gamma -\gamma$ cascades in ${}_{}{}^{171}{}_{}{}^{}\mathrm{Tm}$ populated in the decay of the 7.5 h ${}_{}{}^{171}{}_{}{}^{}\mathrm{Er}$ have been measured to be $W{\left(\theta \right)}_{277.4-210.5}=1+(0.124\mathrm{}\pm 0.005)P_2\left(cos\theta \right)$ and $W{\left(\theta \right)}_{371.9-277.4}=1+(0.018\mathrm{}\pm 0.012)P_2\left(cos\theta \right)$. The result for the first cascade, combined with the existing data on high resolution internal conversion measurements, establishes the spin of the 635.4 keV level to be $\frac{7}{2}$, corresponding to the ${\frac{7}{2}}^{+}\mathrm{}\left[404\right]\mathrm{}$ Nilsson state. The spins of the 912.8 keV ($\frac{5}{2}$) and the 1284.7 keV ($\frac{5}{2}$) levels are in agreement with the angular correlation measurements. The multipole mixing ratios of the transitions are deduced to be: 210.5 keV—$E1+(\lesssim 0.06)\%M2\mathrm{}$; 277.4 keV—$M1+(10\mathrm{}\pm 1)\%E2\mathrm{}$; and 371.9 keV—$M1+(9\mathrm{}\pm 3)\%E2\mathrm{}$. The half-life of the 635.4 keV level has been measured by the $\gamma -\gamma$ delayed coincidence method to be $T_{\frac{1}{2}}=1.26\mathrm{}\pm 0.06$ nsec. The identity of the delayed level has been confirmed by the delayed gating technique. The transition probability of the 210.5 keV $E1\mathrm{}$ transition has been evaluated and compared with the theoretical estimate and that of similar transitions in other nuclei in the region.

RADIOACTIVITY ${}_{}{}^{171}{}_{}{}^{}\mathrm{Er}$ from ${}_{}{}^{170}{}_{}{}^{}\mathrm{Er}$ ($n, \gamma$), measured $\gamma \gamma \left(\theta \right)$, $\gamma \gamma$ delay, $\gamma \gamma$ delayed gating. ${}_{}{}^{171}{}_{}{}^{}\mathrm{Tm}$ levels, deduced $I^{\pi }$, $T_{\frac{1}{2}}$, $\delta$, $T\left(E1\mathrm{}\right)\mathrm{}$, $G_{E1\mathrm{}}$. Enriched target.

A new activity with a half-life of 3.1±0.1 min was observed in bombardments of ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$ with ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ions accelerated in the Oak Ridge isochronous cyclotron. A gas-jet-capillary system was used to transport product nuclei to a shielded area so that singles and coincidence $\gamma$-ray measurements could be made. Only one transition, 620.2±0.1 keV, was found to be associated with this new activity. It was assigned to ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$ because (1) the variation of its yield as a function of bombarding energy was the same as for ${}_{}{}^{148}{}_{}{}^{}\mathrm{Tb}$ $\gamma$ rays, indicating that an equal number of nucleons were evaporated from the compound system, and (2) it was found to be in coincidence with terbium $K$ x rays. No $\gamma$ rays were observed in its coincidence spectrum, and no initial growth period was seen for transitions that follow the decay of the ${}_{}{}^{148}{}_{}{}^{}\mathrm{Tb}$ high-spin isomer. For these reasons the transition very probably proceeds directly to the low-spin isomeric state in ${}_{}{}^{148}{}_{}{}^{}\mathrm{Tb}$ and establishes an intermediate level at ∼620 keV. The spin and parity of this level has to be $1^{+}$ because the transition from the $0^{+}$ ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$ ground state has a $log\mathrm{ft}$ value of 3.9. Our suggestion is that this allowed $\beta$ decay connects states with the following characters: $0^{+} (\pi h_{\frac{11}{2}}, \pi h_{\frac{11}{2}})\to 1^{+} (\pi h_{\frac{11}{2}}, \nu h_{\frac{9}{2}})$. $\gamma$-ray data were also obtained for ${}_{}{}^{149}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{149}{}_{}{}^{}\mathrm{Tb}_{}^m{}_{}{}^{}$. From this information the half-life of ${}_{}{}^{149}{}_{}{}^{}\mathrm{Dy}$ was determined to be 4.1±0.2 min, a value which agrees with recent half-lives reported for this isotope.

RADIOACTIVITY ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$, ${}_{}{}^{149}{}_{}{}^{}\mathrm{Dy}$, ${}_{}{}^{149}{}_{}{}^{}\mathrm{Tb}_{}^m{}_{}{}^{}$; measured $T_{\frac{1}{2}}$, $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ coin; discovered new isotope ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$; ${}_{}{}^{148}{}_{}{}^{}\mathrm{Tb}$, ${}_{}{}^{149}{}_{}{}^{}\mathrm{Gd}$ deduced levels, $J$, $\pi$.

The half-life of ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$ relative to the half-life of ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}$ has been found to be $\frac{t_{\frac{1}{2}}^{128}}{t_{\frac{1}{2}}^{130}}=(1.59\mathrm{}\pm 0.05)\times {10}^3$ by measurement of the $\beta \beta$-decay products, ${}_{}{}^{128}{}_{}{}^{}\mathrm{Xe}$ and ${}_{}{}^{130}{}_{}{}^{}\mathrm{Xe}$, in a geologically old (2.4×${10}^9$ yr) telluride ore. These results yield an upper limit on the lepton nonconservation parameter, $\eta \le 0.8\times {10}^{-4\mathrm{}}$.

RADIOACTIVITY $\beta \beta$-decay ${}_{}{}^{128}{}_{}{}^{}\mathrm{Te}$; measured $T_{\frac{1}{2}}=1.5\mathrm{}\times {10}^{24}$ yr; deduced $\eta \le 0.8\times {10}^{-4\mathrm{}}$. Detected excess ${}_{}{}^{128}{}_{}{}^{}\mathrm{Xe}$ in old Te ore.

The energies and intensities of $\gamma$ rays and internal-conversion electrons from the electron-capture decay of ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ and from the $\alpha$ decays of ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ and ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$ have been measured. A new first-forbidden electron-capture branch of ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ is reported. First-forbidden electron-capture transition rates are discussed with reference to the $2g_{\frac{9}{2}}$ and $1i_{\frac{11}{2}}$ neutron states in ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$. $\gamma$ rays corresponding to the $l$-forbidden $M1\mathrm{}$ transitions $\nu {\left(3\mathrm{}{p}_{\frac{3}{2}}\right)}^{-1\mathrm{}}\to \nu {\left(2\mathrm{}{f}_{\frac{5}{2}}\right)}^{-1\mathrm{}}$ in ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ and $\nu \left(1\mathrm{}{i}_{\frac{11}{2}}\right)\to \nu \left(2\mathrm{}{g}_{\frac{9}{2}}\right)$ in ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$ have been observed. The $\alpha$ spectra of ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ and ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$ and the energies and relative intensities of $\gamma$ rays from the electron-capture decay of ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ have been remeasured. A level scheme incorporating all of these decays is given.

RADIOACTIVITY ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ [from ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}(\alpha , 2n)$]; measured $E_{\gamma }$, $I_{\gamma }$, $I_{\mathrm{ce}}$, $I_{\alpha }$; deduced $log\mathrm{ft}$, EC branching, $\alpha$ branching. ${}_{}{}^{211}{}_{}{}^{}\mathrm{Po}$, ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$, ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ deduced levels, $J$, $\pi$, ICC, $\gamma$ multipolarity, $\gamma$ branching. Ge(Li), Si(Li), Au-Si detectors.

The mass differences of 17 doublets involving the atoms ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ have been measured with a rf mass spectrometer. By least squares adjustment, best values are obtained for the masses of these eight atoms for which the estimated errors are materially less than for previously published values. By using Einstein's mass energy relation, very accurate values are derived for the $\beta$ decay energies of ${}_{}{}^3{}_{}{}^{}\mathrm{H}$ and ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ and for the neutron binding energies in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$. The last ones offer a possibility to improve the calibration for multi-MeV (capture) $\gamma$ rays by an order of magnitude.

NUCLEAR STRUCTURE ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ measured atomic mass. ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ deduced $Q^{-}$. ${}_{}{}^2{}_{}{}^{}\mathrm{H}(n, \gamma )$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}(n, \gamma )$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(n, \gamma )$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}(n, \gamma )$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(n, \gamma )$ deduced $Q$.

Thermal neutron capture and average resonance neutron capture in ${}_{}{}^{183}{}_{}{}^{}\mathrm{W}$ yield two different $\gamma$-ray spectra made up of high energy primary transitions from the capture state to low-lying levels in ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$. These spectra along with medium energy spectra following thermal capture and $\gamma -\gamma$ coincidence spectra produced from $\beta$ decay of ${}_{}{}^{184}{}_{}{}^{}\mathrm{Re}$ provides the basis for the study of 43 states in ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$ ranging in energy up to 2404 keV. A level scheme has been constructed that incorporates 50 $\gamma$ rays having energies ranging from 600 to 2400 keV. Five energy levels not previously reported in the literature have been discovered and $J^{\pi }$ assignments for over six other levels have been improved so that parities are certain in most cases while spin choices are narrowed to at most two. All positive parity states below 2404 keV having spins 0, 1, or 2 have been detected and most if not all have been given a definitive positive parity assignment. In addition, many negative parity states having low spin values have been identified. Disagreements with $J^{\pi }$ assignments previously reported in the literature are discussed.

NUCLEAR STRUCTURE ${}_{}{}^{183}{}_{}{}^{}\mathrm{W}(n, \gamma )$ $E_{\gamma }=607\mathrm{} \mathrm{keV}-2690\mathrm{} \mathrm{keV}$. ${}_{}{}^{183}{}_{}{}^{}\mathrm{W}(\overline{n}, \gamma )$ $E_{\gamma }=5008\mathrm{} \mathrm{keV}-7412\mathrm{} \mathrm{keV}$, Ge(Li) detector; deduced ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$ levels, $J$, $\pi$. ${}_{}{}^{184}{}_{}{}^{}\mathrm{Re}$, ${}_{}{}^{184}{}_{}{}^{}\mathrm{Re}_{}^m{}_{}{}^{}$ $\beta$, $\gamma \gamma$-coin, ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}$ levels.

The Sussex harmonic oscillator matrix elements are employed to estimate the effect of cross terms between the nuclear interaction and the Coulomb potential. The 2p, 3p1h, and 4p2h corrections are calculated with second order perturbation theory. The resulting matrix elements of the charge dependent interaction yield excellent agreement with observed isospin mixing in ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$. Comparison is made to $G$-matrix calculations.

NUCLEAR STRUCTURE Sussex matrix elements. Coulomb shifts. Isospin mixing ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$.