Revamping of a diagnostic neutral beam injector for a reversed field pinch experiment

The injection of a neutral beam in toroidal magnetic confined plasmas is a well established method to measure ion flow, impurity content, ion temperature, besides intensity and direction of the magnetic field. While this diagnostic method was extensively explored in Tokamak plasmas, only little experimentation has been carried out in reversed field pinch (RFP) plasmas so far. Characterizing the magnetic field in the center of the plasma is especially relevant for RFPs, in order to properly reconstruct the magnetic configuration. For this reason the Diagnostic Neutral Beam Injector (DNBI) of the RXF-mod2 experiment in Consorzio RFX, Padua, is object of deep maintenance and upgrade. Several DNBI plants (electrical, control and data acquisition, vacuum pumping, etc.) will be renovated for improved performances and reliability. Numerical simulations are ongoing in order to properly design the duct connecting the DNBI to the toroidal chamber, so to minimize the beam reionization losses inside the duct. This contribution discusses the technical improvements and the physics studies which led to the final design of the entire DNBI diagnostic system.