A NON INVASIVE TECHNIQUE FOR THE TRANSVERSE MATCHING IN A PERIODIC FOCUSING CHANNEL OF A LINAC

A main interest in the high intensity ion linacs is the control of the particle loss in the vacuum chamber. A extremely low fraction of the beam, from 10−7 up to 10−4, is sufficient to complicate the hands on maintenance in such accelerator. Beam mismatching being a major source of halo, it is proposed a non invasive technique to adapt the beam to a periodic focusing channel of a linac based on a FDO of FODO lattice. It is demonstrated that only the matched beam can correspond to a particular signature of the quadrupolar moment of the Beam Positions Monitors. This technique allows also to measure the emittance value or evolution along the channel.