Study of nuclear reactions with intense, high-purity, low-energy radioactive ion beams using a versatile multi-configuration dual superconducting-solenoid system
Abstract A new device (TwinSol) installed at the Nuclear Structure Laboratory at the University of Notre Dame implements a pair of large-bore 6 T superconducting solenoids for producing relatively pure, high-intensity beams of exotic light nuclei at low-energies (10–80 MeV). Typical beams include 8 Li and 6 He (T 1/2
Measurement of the 6Li + natSi reaction cross section at 18 to 28 MeV with a magnetic spectrograph and position-sensitive Si detector
Abstract The average reaction cross section σ R for 6 Li in nat Si was determined from the 6 Li energy spectrum in a two-dimensional position-sensitive Si detector in the focal plane of a magnetic spectrograph. The average σ R for 18 to 28 MeV 6 Li, 1490±80 mb, is compared with specific optical and strong absorption model calculations. Good agreement is obtained for certain models. This method for measuring σ R may be particularly useful when only small particle fluxes (≤100/s) are available; e.g., for radioactive nuclear beams.
Systematics of 8Li-induced radioactive beam reactions: E=13-20 MeV.
Elastic and inelastic scattering, one-nucleon transfers [mostly ${(}^{8}$Li, $^{7}\mathrm{Li}$)] and the ${(}^{8}$Li,\ensuremath{\alpha}) fusion-evaporation reaction have been studied on a variety of targets (A=1--58) at E${(}^{8}$Li)\ensuremath{\approxeq}13--20 MeV using the University of Michigan--University of Notre Dame radioactive nuclear beam (RNB) facility. The latter, which produces an energy-resolved (\ensuremath{\sim}500 keV FWHM), focused beam with intensity \ensuremath{\gtrsim}${10}^{6}$ $^{8}\mathrm{Li}$/s, permitted measurements to selected nuclear levels with cross sections down to approximately 1 mb/sr. Based on the systematics of the measured $^{8}\mathrm{Li}$ elastic scattering an appropriate $^{8}\mathrm{Li}$ optical potential was deduced. Large inelastic scattering cross sections (and B[E2\ensuremath{\uparrow}]) are observed for $^{8}\ensuremath{\rightarrow}^{8}$${\mathrm{Li}}_{0.98}^{\mathrm{*}}$. Large cross sections are also observed for the ${(}^{8}$Li${,}^{7}$Li) transfer reaction corresponding to quasielastic (viz., Q\ensuremath{\approxeq}0) neutron transfer to selected high spin excited levels in the residual nucleus. The ${(}^{8}$Li,\ensuremath{\alpha}) fusion-evaporation reaction also appears to be significant and can produce very-high-energy \ensuremath{\alpha} particles, viz., ${\mathit{E}}_{\mathrm{\ensuremath{\alpha}}}$\ensuremath{\gg}${\mathit{E}}_{\mathrm{beam}}$. Although observed using $^{8}\mathrm{Li}$, these features appear to be important for many RNB-induced reactions and they must be considered, for example, in nucleosyntheis calculations involving $^{8}\mathrm{Li}$ and other short-lived radioactive nuclei.