Superconducting cyclotrons for acceleration of H2+

The use of cyclotrons to produce high intensity beams offers many advantages with respect to linear accelerators: compactness, lower cost and higher electrical-beam power conversion efficiency. According to the positive experience of the PSI laboratory, the cyclotrons proposed up to now to deliver high intensity beams are based on extraction by electrostatic deflectors. In this case a large extraction radius and high energy gain per turn are required. An alternative method based on acceleration of H-2(+) ions is proposed here. The binding energy of a H-2(+) molecule is about 20 times higher than H-, and also allows to use very high magnetic fields at energies as high as 1 GeV/n. The maximum beam current achievable with these cyclotrons is extrapolated from the experimental results obtained by H- commercial cyclotrons. The main advantages, i.e. easy operation, high reliability and electrical conversion efficiency and the technological problems of this alternative method are presented.