ENHANCEMENT OF ECR PERFORMANCES BY MEANS OF CARBON NANOTUBES BASED ELECTRON GUNS

The CANTES experiment at INFN-LNS tested the use of carbon nanotubes (CNTs) to emit electrons by field emission effect, in order to provide additional electrons to the plasma core of an ECR ion source. This technique was used with the Caesar source, demonstrating that the total extracted ion current is increased and that a relevant reduction of the number of "high energy" electrons (above 100 keV) may be observed. The injection of additional electrons inside the plasma increases the amount of cold and warm electrons, and then the number of ionizing collisions. Details of the construction of CNTs based electron gun and of the improvement of performances of the Caesar ECR ion source will be presented.