Interstrand coupling losses of Rutherford cables

Interstrand coupling losses of Rutherford cables are easily affected by curing conditions. We have measured the interstrand coupling losses and contact resistances for three kinds of Rutherford cable, made from strands with a Cu matrix, a CuMn barrier around a filamentary bundle and a CuMn matrix inside a Cu sheath. Furthermore we have observed the contact surfaces of the strands by using a scanning electron microscope. We have found that strands of cables with a Cu surface were bonded at crossover points cured at higher temperatures, and there were traces of diffusion bonding on the contact surfaces. We have also investigated the mechanical properties of the matrix materials and reviewed the fabrication process of magnets in which pressure is released after curing. We have concluded that the losses are determined by a balance between bonding forces and spring back of the strands. (C) 1996 Elsevier Science Limited