LINAC 2 prototype

Prototype of Linac 2, a Linear proton accelerator used in the PS (proton synchrotron accelerator injection system). A Linearaccelerator is a particle accelerator which accelerates charged particles - electrons, protons or heavy ions - in a straight line. Charged particles enter at one end and are accelerated towards the first drift tube by an electric field. Once inside the drift tube, they are shielded from the field and drift through at a constant velocity. When they arrive at the next gap, the field accelerates them again until they reach the next drift tube. This continues, with the particles picking up more and more energy in each gap, until they shoot out of the accelerator at the other end. Linac 2,also called Alvarez Proton Linac, was first run in 1978 and is still running today. It provides pulsed (1 Hz) beams of up to 170 mA at 50 MeV with pulse lengths varying between 20 and 150 ms depending on the number of protons required.