STUDY OF A HIGH-CURRENT 176 MHZ RFQ AS A DEUTERON INJECTOR FOR THE SPES PROJECT

Abstract Since external forces scale as (q and internal forces according to / A) V⋅ (q / A) I ⋅ , the beam dynamics is exactly the same for deuterons with a beam current of 6 mA and a inter vane voltage of 2 / of the nominal case. Moreover, to improve the deuteron transmission, there is the possibility to increase the voltage and the surface field to 1.8 Kilpatrick. 3 The SPES project[1], aimed at the construction of a RIB facility at LNL, is based on the use of a primary beam of protons, and foresees a further development based on the acceleration of deuterons and light ions. In this article we report about the preliminary study of a 176 MHz RFQ to be used as an injector for such kind of beams. The structure explored foresees a four ladder symmetric resonator, built in brazed copper. In particular beam dynamics, electrodynamics design and preliminary thermo-structural analysis of the cavity is presented. Simulations show that high transmission, more than 90%, required the focusing force, represented by the B focusing parameter, takes more than 40 % of the overall electric field; this is important above all in the shaper and bunching sections. We know that the higher is B the lower is the accelerating force, represented by A accelerating parameter, which influences the RFQ length