The decay scheme of $^{20}\mathrm{Na}$ has been studied in detail to obtain information on the $\ensuremath{\beta}$-decay mirror symmetry properties of the mass-20 multiplet and to determine the Fermi decay strength to the $T=1$ isobaric analog state in $^{20}\mathrm{Ne}$. The ratio $\frac{{\mathrm{ft}}^{+}}{{\mathrm{ft}}^{\ensuremath{-}}}$ was determined to be 1.026 \ifmmode\pm\else\textpm\fi{} 0.024 for the ${\ensuremath{\beta}}^{+}$ transitions to the first excited state of $^{20}\mathrm{Ne}$. The $\mathrm{ft}$ value for the transition to the $T=1, 10.278$-MeV level was measured to be 2992 \ifmmode\pm\else\textpm\fi{} 233 sec indicating that most of the Fermi strength is concentrated in this transition. A weak $\ensuremath{\gamma}$ transition from the ${2}^{+}$ isobaric analog state to the ${2}^{+}$ first excited state of $^{20}\mathrm{Ne}$ was observed and new ${\ensuremath{\beta}}^{+}$-delayed $\ensuremath{\alpha}$ groups are reported at 3.27, 5.272, and 5.701 MeV. Theoretical $\mathrm{ft}$ values derived from the shell-model wave functions are compared with experiment.

Alpha particles emitted from levels in 24Mg following the β-decay of 24Al have been measured. In addition to the α-groups previously reported in the β-decay of the 4+ ground state of 24Al, new groups were observed as a result of using special techniques to reduce the β-background and to increase particle energy resolution. Alpha-particle groups associated with the β-decay of the 1+ isomeric state of 24Al were observed for the first time. The α-particle transitions observed in this work have been correlated with known energy levels. Log ft values have been calculated or estimated from the relative intensities of the delayed α-particle groups.

An analysis of the line shapes of α-particle groups from the β-delayed α-particle decay of 20Na has revealed a simple method of obtaining β+−ν anisotropy coefficients and F/GT ratios. Evidence has been obtained for existence of a longitudinal nuclear alignment of β-recoils from G-T-transitions.

A recent study of the alpha spectrum of $sup 23$Na under conditions of high energy resolution is reported from which one can obtain directly from the alpha spectrum a partial level scheme. In addition it is possible to obtain beta decay Q values and some qualitative information on $beta$$sup +$ - $nu$ correlations from the measured shapes of the individual alpha lines. The line broadening is also discussed. (JFP)

The helium-jet recoil transport method has been improved for the study of nuclei with half-lives less than 1 msec. Effects of the thermalizing medium, turbulence and properties of the gas jet on the collection speed and efficiency have been studied using short-lived α-emitters produced in heavy-ion reactions. Possibilities for on-line chemical separations are discussed.

The thermal neutron (n, γα) reaction has been detected for the first time. Alpha transitions were observed from levels in 144Nd 1 to 2 MeV below the thermal neutron capture state, in addition to transitions from the capture state to low-lying levels of 140Ce.

A technique has been developed to transport tritons, alphas and fission fragments from high flux regions around a reactor core to distances several meters from the source. The method is being used for high resolution studies of thermal neutron (n, α) reactions and as a means of obtaining intense fluxes of fission fragments.