Nano-motion control of heavy quadrupoles for future particle colliders: An experimental validation

This paper presents an experimental validation of a control strategy capable of both stabilizing and positioning the heavy electromagnets of future particle colliders. The originality of the approach is to use the same active mounts to perform both tasks, with a nanometer precision. In a previous paper, the concept has been studied numerically, and validated on a scaled single degree of freedom (d.o.f.) test bench. In this paper, it is extended to a two d.o.f. test bench, constituted of a heavy mass mounted on two active legs. Firstly, the model is described and the performances are discussed numerically. Secondly, experimental results are presented, and found to correlate well with the model, and comply with the requirements. Finally, the experimental results are combined with a simplified model of the beam-based feedback to evaluate the jitter of the beam. It is found that, at the scale of a single quadrupole, the mechanical stabilization of the quadrupoles reduces the vertical beam jitter by a factor 10.