Superconductor Deformation

Superconductors are deformed through the cabling process. In case of severe deformation, they are damaged. Tin leaks in a Nb3Sn conductor and cut filamnts are the problems in superconductors. FEM anlysis gives a viw in how the deformation of the conductor develops.

Single strad



Strands are deformed at the cable edge. This deformation resembles to a formation of square shaped conductor. Superconductors are deformed also to make a monolisic conductor.






















Compacted strand cable



"Rutherford type" compacted strand is a common cable for accelerator dipole and quadrupole magnet.strands are gatherd and compacted to form a rectangulare shape. This is a symmmetric rectangl but practical cables are Keystoned to accomodate the radial alignment.














Compacted strand cable at the odd location


Since strands are transposed, some strand has to move to other layer at the edge. This is where the most severe deformation occures.














Deformation in side the strand

Strands are deformed through cabling. The problem is the sevear deformation in a strand. If the barrier is cut due to deformation, it causes tin leakage nn case of Nb3Sn conductor.
However, the deformation of modules inside a strand is not as much as it looks from the deformation of strand. This is because the deformation is divided into the location change of modeules and the deformation of modules themselves. Conductors shuld stand for farely severe deformation if the material is uniform. As a matter of fact, conductor material is very un-uniform in the level of hundredth of mm. Dislocations and grain boundaries appears at every where. Tin leaks comes from such inhomegneity of materials.