Particle accelerators typically whip charged particles around using magnetic and electric fields, enabling physicists to investigate high-energy collisions. Peter Zieger of the Fritz Haber Institute in Berlin and his colleagues have built a prototype molecular synchrotron for neutral molecules, a key step towards studying low-energy collisions.
Using specially designed electric fields, the team managed to keep ammonia molecules centred as they whizzed around a 0.5-metre-diameter ring (pictured). Varying the strength of the electric fields allowed the group to keep the molecules grouped in 'bunches'. Bunching up the molecules should increase the sensitivity of future collision studies.