A cyclotron is a particle accelerator in which ions are accelerated as they orbit in a magnetic field. In the simplest form it consists of a uniform magnetic field, B. The circular area is divided into two D-shaped regions ("dees"), one of which is held at earth potential while an alternating potential is applied to the other. Ions produced in an ion source near the centre of the area travel in circular orbits. As they cross the gap between the two dees they gain energy from the potential difference and so the radius of their orbit increases. Ions spiral outwards, acquiring energy on each orbit, until at the outside of the cyclotron they reach their full energy.
A switching magnet directs the beam in one of 12 possible directions. One of these directions leads to a radiation box, held in place by a robot. The target of the irradiation experiment is placed inside this box.
The robot has two motors at 90 degrees. One moving the box up and down, the other left and right. The robot moves the box through the beam (which is only 1cm2) at constant velocity, so that the samples inside are irradiated evenly.