If the alpha particles, protons and deuterons are imparted with the high velocity then they can be made more effective. For this purpose many instruments have been developed for increasing the speed of particles.
E.O. Lawrence developed the most effective instrument for this which is known as Cyclotron.
It consists of many parts like two flat semi-circular boxes called Dees which are marked as D1 and D2 shown below
The Dees are surrounded by vessel containing hydrogen, deuterium or helium gas which is at low pressure. The vessel is kept between the electromagnet poles as shown in fig.2 (b) (check below). Alternating potential of high frequency of million cycles/second is applied across D1 and D2. By electron bombardment of hydrogen, deuterium or helium positive ions are produced.
Let at a particular moment, the direction of potential applied is like that D1 is positive and D2 is negative. From A, positive ion will start and moved into D2. It will follow a semicircular path. The path is semicircular because of deflection which is caused by magnetic field. The ion get exposed when it reaches between the gap of D1 and D2 due to the influence created by potential applied. If the potential is reversed i.e. D1 gets negative and D2 becomes positive then the ion will start moving towards D1. By this the ion will start moving faster than before and hence the path of the radius increases. But the traversing time taken by the ion remains unchanged i.e. remains same. This is because the path that gets increased was compensated by the ion having increased speed. This means the ion would remain in phase by proper adjustment of oscillation frequency.
