TITANIUM NITRIDE INSULATION FOR THE DEFLECTOR OF SUPERCONDUCTING CYCLOTRONS

At the Istituto Nazionale di Fisica Nucleare-Laboratorio Nazionale def Sud of Catania (Italy) during the last years a research program has b een carried out to improve the performance of the superconducting cycl otron electrostatic deflectors, In this kind of accelerators beam extr action is realized by means of two electrostatic deflectors generating a 140 kV/cm maximum electric field in a small gay (6 to 8 mm). These devices have to work in presence of a high magnetic field (less than o r equal to 5 T), strongly affecting their performance from the electro static Feint of view, This is mainly the focusing of the electrons emi tted by the cathode for field effect, The physical characteristics of the cathode surface influence the electrostatic behavior especially in terms of work function and resistivity. Moreover, the mechanical prop erties of the surface have to be studied in order to evaluate the effe cts of high power beam dissipation on the cathode during the extractio n process in the accelerator, also influencing the electrostatic perfo rmance. Looking to these constraints, a detailed study of the TIN (tit anium nitride) features for this application has been carried out, Con sidering the electrical and mechanical properties, TIN seems to be a m aterial suitable for this application Electrostatic tests carried out in a deflector simulator confirm that TIN should represent an attracti ve solution, The results obtained with a surface characterization base d on different physical analysis methods will be presented.