Operation of the Orsay Cevil and Its Extraction Systems

It is possible to obtain an isochronous magnetic field over a wide range of average induction for a given ion by changing the structure of the electro-magnet. This new structure allows great reduction of correcting adjustements. We obtained, at Orsay, encouraging results by the use of shims with variable permeability and damping gaps. Only two correction coils were necessary to make the average field isochronous to within 30 gauss, for all the ions. The internal beam tests confirmed the good quality of the magnetic field and verified the theoretical calculations ; the intensity of the multicharged ion beam was generally greater than the initial evaluation. Two extractors are at present set up : an electrostatic deflector and a stripping extractor. This latter device perserves the optical qualities of the beam. Furthermore, one or more simultaneous beams can be obtained with an excellent efficiency, and with various energies, depending on the radius.