Vacuum System for the Accelerating Structure of the Ifusp Microtron

The Laboratório do Acelerador Linear do Instituto de Física da Universidade de São Paulo (LAL-IFUSP) finished the construction of a β = 1 continuous wave accelerating structure [1] for the IFUSP microtron [2], which presented excellent properties [3]. The structure is a 1.04-m long standing wave, side coupled (SCS) design, with 17 accelerating cavities and 16 coupling cavities. One of the main advantages of the side-coupled accelerating structure, as compared to other structure designs, is the possibility of pumping each of the coupling cavities. This is an important feature, for it allows a quick pumping of the degassing produced by RF heating or sparking in the structure. Our structure presents 16 coupling cavities, each of them connected by a tube with a conductance of 12 l/s. Figure 1 shows a schematic drawing of the structure, with dimensions and details of the cavities.