Double-peak structures in transmission of H2 + ions through conical multicapillaries in a polymer: Projectile-energy dependence

Transmission experiments of 7–200 keV H2+ ions through conical multicapillaries with inlet or outlet diameters of 4/2 μm and a length of 30 μm etched in a PC polymer are reported. The yield of the transmitted particles as a function of the capillary tilt angle was measured. The results show that for 200 keV H2+ ions the guiding effect disappears but a focusing effect is obtained with a density enhancement factor of 3.5. For 7–50 keV H2+ ions their transmitted particle curves exhibit a pair of shoulder peaks on the leftand right-hand side of the center angle 0◦. As the ion energy increases, the shoulder-peak structure is found to vanish leaving one peak at 0◦.