Contact Surfaces between Strands of Rutherford Cables in Various Curing Conditions
Interstrand AC losses and contact resistances of Rutherford cables are easily affected by curing conditions. We have measured the interstrand AC losses and contact resistances for three kinds of Rutherford cables, made from strands with a Cu matrix, a CuMn barrier around a filamentary bundle and a CuMn matrix inside a Cu sheath. The losses of all the cables were relatively large, if there was no release of pressure after curing. They were significantly reduced after releasing the pressure at a room temperature except for the cable with a Cu matrix at a high curing temperature. The measured contact resistances show the same dependencies. Strands of the cable with a Cu matrix were bonded at crossover points by curing at higher temperature, and bonded crossover points were not broken when pressure is released after curing. We have also observed contact surfaces of the strands by using a Scanning Electron Microscope, and found that there were traces of diffusion bonding on the contact surfaces. The fact that the other cables show smaller AC losses by releasing pressure can be explained by the mechanical properties of the matrix materials.
KeywordsContact Resistance Crossover Point Diffusion Bonding Diffusion Welding High Energy Accelerator
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