[en] The charged-particle microbeam provides a unique opportunity to precisely control both the dose to individual cells and the localization of dose within the cell. In the Gray Laboratory, both the performance of the detection system and the targeting system has been assessed for 3.5 MeV ³He²⁺ ions. Using an 18 μm transmission scintillator and a photomultiplier tube as the particle detection system, detection efficiency is higher than 99%. When a 5 μm collimator is used, the overall targeting accuracy (which includes the error associated with target finding and alignment) is <2.8 μm for 98.7% of hits