Experimental validation of an innovative deflection compensation method in a multi-beamlet negative-ion accelerator

An innovative magnetic configuration called ADCM (Asymmetric Deflection Compensation Magnets) has been recently proposed for the cancellation of the "criss-cross" deflection of ion trajectories in multi-beamlet negative ion accelerators. Such undesired deflection occurs due to the transverse magnetic field, which is necessary for the suppression of co-extracted electrons. In view of the application of this concept to the ITER Heating Neutral Beam Injector, the new configuration has been experimentally tested for the first time in 2016, in the framework of a research collaboration between Consorzio RFX and QST.