We have used the Pelletron in our nuclear physics course since 1990. Sessions in the accelerator lab are run with a tecnician and a faculty member. At the beginning of each session, students are assigned specific jobs and learn about their duties for that day.
Jobs typically rotate from week to week.
Our experience suggests that about three students per laboratory session is optimal, although we have operated with twice that many. The students keep each other informed about the progress of the experiment. The detectors are cabled and the accelerator is started before the first session. Students are actively involved in testing and calibrating electronics, debugging problems, and repairing or replacing defective equipment. Since an experiment usually takes at least four or five hours to complete, no single group of students observes the whole process.