Beam-pipe coupling in particle accelerators by shape memory alloy rings

Shape Memory Alloy (SMA) rings have been studied for possible applications as beam-pipe connectors in particle accelerators. The rings were analyzed by both experimental tests and finite element simulations. In particular, the tightening performance of NiTiNb rings, in terms of contact pressure and clamping/unclamping mechanisms, was studied for different values of the initial clearance between ring and vacuum pipe. The results have revealed that the contact pressure is not significantly affected by the assembly clearance due to the plateau in the stress-strain response of the material. In addition, thermal dismounting and subsequent re-clamping is obtained by exploiting the two way shape memory recovery capabilities of the SMA rings. Thanks to these features, these connectors can be used in high-energy particle accelerators, especially in radioactive areas, where thermally induced mounting and dismounting operations can be activated remotely.