Collimated-hole structures as efficient differential pumping barrier, one-way valve and tool for aligning Penning traps

A collimated-hole structure consists of a very large number of parallel channels which have each a very small diameter and are closely packed together. Such devices, installed in vacuum systems allow one to separate regions of very different gas pressures. A collimated-hole structure has high transmission for a directed ion beam with low emittance but a very low conductance for rest gas atoms or molecules exhibiting random walk. Therefore it is proposed to use such a structure as one-way valve and/or efficient differential pumping barrier in set-ups using Penning traps. Furthermore, these devices might be very useful to align the axis of a Penning trap with the direction of the magnetic field lines which is essential to avoid systematic uncertainties in high-accuracy mass spectroscopy.