A molecular merry-go-round

John Fenn’s foreword to Atomic and Molecular Beam Methods (volume 1, Oxford University Press, 1988) included the following testimonial about molecular beams: “Born in leaks, the original sin of vacuum technology, molecular beams are collimated wisps of molecules traversing the chambered void that is their theatre. . . . On stage for only milliseconds between their entrances and exits, they have captivated an ever growing audience by the variety and range of their repertoire.” The tiny millisecond performance time results from the molecules moving quickly—hundreds of meters per second—and acting in a 1-m-long vacuum chamber. In a molecular synchrotron, however, slowed neutral molecules travel inside a circular 1-m vacuum chamber for more than a mile and thus stretch the duration of their performance by a factor of 10 000. The molecular synchrotron was developed by Gerard Meijer and coworkers, who began their work a decade ago at the FOM Institute...