Interactions of fast HeH+beams with matter

We present experimental results from high-resolution studies of the energy and angle distributions for the breakup products that arise from the dissociation of fast-moving ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ ${\mathrm{H}}^{+}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ${\mathrm{H}}^{+}$ in thin carbon foils. These results are compared with calculations based on a model for the polarization "wakes" induced in foils by the passage of fast charged projectiles. We also describe measurements on the transmission of such fast molecular ions through thin foils and present results on the transmission probabilities, energy losses, and angular distributions of the transmitted ions. A mechanism is proposed to account for these observations on molecular-ion transmission. Related studies on the foil-induced dissociation of O${\mathrm{H}}^{+}$, O$\mathrm{H}_2^{}{}_{}{}^{+}$, C${\mathrm{H}}^{+}$, $\mathrm{H}_2^{}{}_{}{}^{+}$, and ${}_{}{}^3{}_{}{}^{}\mathrm{He}_2^{}{}_{}{}^{+}$ are also briefly reported.