EBIS, an option for medical synchrotrons

Light ion beams have been used for cancer therapy for about twenty years; several dedicated facilities are presently either planned or under construction. In addition, several synchrotrons designed for other purposes are now considered for medical applications as well. A medical synchrotron needs a preaccelerator to produce and inject a range of different light ions, preferably fully stripped, into the ring. The size, cost and complexity of the preaccelerator depend on the performance of its first element, the ion source, and these features will be optimized if the source itself produces fully stripped ions. An EBIS (Electron Beam Ion Source) is capable of producing fully stripped light ions up to argon with intensities sufficient for medical applications. As it has been pointed out in the past, this source option may require just one stage of preacceleration, an RFQ linac, thus making it very simple and compact. The AGS Department has a separate project already under way to develop a very high intensity EBIS for our nuclear physics program. It is, however, our plan first to construct and test an intermediate size device and then to proceed to the design of the final, full scale device. Parameters of that intermediate model are close to those that would be needed for a medical synchrotron. This paper describes the BNL program and considers parameters of EBIS devices for possible use in synchrotron facilities serving as sources of high energy light ions for cancer therapy