The Diaphragm Centering Technique, based on an innovative use of plates, has originally been developed to center and clamp superconducting coils of CERN’s LHC Corrector magnets.

In those magnets, external shrinking cylinders are used to compress the inner cylindrical coil body.

However, the space between the shrinking cylinder and the coil body is occupied by the iron yoke consisting of a stack of iron, ring shaped, laminations that normally would block the pre-stress induced by the outer shrinking cylinder.

Problem: How can we achieve that the shrinking pressure, exerted by the shrinking cylinder on these iron ring laminations, shall pre-stress the inner coil body?

The “Diaphragm technique” solves this in a surprisingly simple and elegant way:

1. It gives the iron rings a slight eccentricity of a few tenths of a millimeter
2. It stacks the rings in different angular orientations