Recoil decay tagging (RDT) is a very powerful method for the spectroscopy of exotic nuclei. RDT is a delayed coincidence technique between detectors usually at the target position and at the focal plane of a spectrometer. Such measurements are often limited by dead time. This paper describes a novel triggerless data acquisition method, which is being developed for the Gamma Recoil Electron Alpha Tagging (GREAT) spectrometer, that overcomes this limitation by virtually eliminating dead time. Our solution is a total data readout (TDR) method where all channels run independently and are associated in software to reconstruct events. The TDR method allows all the data from both target position and focal plane to be collected with practically no dead-time losses. Each data word is associated with a timestamp generated from a global 100-MHz clock. Events are then reconstructed in real time in the event builder using temporal and spatial associations defined by the physics of the experiment.

The difference in the energies of the lowest states corresponding to the two nodeless single-particle orbitals outside the $Z=50$ closed proton shell, $h_{11/2}$ and $g_{7/2}$, increases with neutron excess. We have measured the Sn$(\alpha ,t)$ reaction for all seven stable even Sn isotopes and found that the spectroscopic factors are constant for these two states, confirming their characterization as single-particle states. The trend in energies is consistent with a decrease in the nuclear spin-orbit interaction. A similar trend, also suggesting a decreasing spin-orbit splitting, is seen in the energies of the neutron single-particle states outside the $N=82$ core, $i_{13/2}$ and $h_{9/2}$.

The even ${}^{52-56}\mathrm{Ti}$ isotopes have been studied with intermediate-energy Coulomb excitation and absolute $B(E2;0^{+}\to 2_1^{+})$ transition rates have been obtained. These data confirm the presence of a subshell closure at neutron number $N=32$ in neutron-rich nuclei above the doubly magic nucleus ${}^{48}\mathrm{Ca}$ and provide no direct evidence for the predicted $N=34$ closure. Large-scale shell model calculations with the most recent effective interactions are unable to reproduce the magnitude of the measured strengths in the semimagic Ti nuclei and their strong variation with neutron number.

The possibility of observing neutrinoless double $\beta$ decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and measurements of the occupations of valence orbits by nucleons active in the decay can be important. The occupation of valence neutron orbits in the ground states of ${}^{76}\mathrm{Ge}$ (a candidate for such decay) and ${}^{76}\mathrm{Se}$ (the daughter nucleus) were determined by precisely measuring cross sections for both neutron-adding and removing transfer reactions. Our results indicate that the Fermi surface is much more diffuse than in theoretical calculations. We find that the populations of at least three orbits change significantly between these two ground states while in the calculations, the changes are confined primarily to one orbit.

The two-proton knockout reaction ${}^9\mathrm{Be}$(${}^{54}\mathrm{Ti}$,${}^{52}\mathrm{Ca}+\gamma$) has been studied at 72 MeV/nucleon. Besides the strong feeding of the ${}^{52}\mathrm{Ca}$ ground state, the only other sizeable cross section proceeds to a $3^{-}$ level at 3.9 MeV. There is no measurable direct yield to the first excited $2^{+}$ state at 2.6 MeV. The results illustrate the potential of such direct reactions for exploring cross-shell proton excitations in neutron-rich nuclei and confirms the doubly-magic nature of ${}^{52}\mathrm{Ca}$.