Experimental characterization of the internal ion source for the AMIT compact cyclotron

The ion source is one of the most relevant elements in a cyclotron, since it determines the injection into the accelerator. An internal cold-cathode Penning ion source has been chosen for the AMIT compact cyclotron. This kind of source is extensively used in cyclotrons to produce negative hydrogen ions. The compactness of the accelerator constrain the beam diagnostic in the cyclotron, motivating the development of an external experimental facility for the commissioning of the ion source. In this paper, the validation of the ion source design and the characterization of the H− beam production are presented. Different chimney geometries modifying the distance between the plasma column and the extraction wall have been tested to obtain the best relation between ion production and plasma conditions. In addition, experimental measurements of the beam profile have been carried out. Current experimental results provide relevant information for the operation in the final cyclotron assembly and the final beam current optimization.