Vacuum chamber made of soft magnetic material with high permeability

Kamiya, Junichiro   ; Ogiwara, Norio; Nishikawa, Masaaki; Hikichi, Yusuke; Yanagibashi, Toru; Kinsho, Michikazu  

One of the reasons of a beam loss in a high power accelerator is leakage magnetic field from a magnet at a close beam line, which distorts the beam orbit and makes the beam hit the wall of the beam pipe. The most effective way to shield such leakage field is to cover the beam by the magnetic materials at the nearest space. This means that vacuum chambers should be made of the magnetic materials. We selected the permalloy, which has very high magnetic permeability for such a magnetic material. However, there is not proven evidence of the vacuum chambers, which are made of magnetic materials. We have developed a vacuum chamber of such new material with the object of vacuum and magnetic characteristics.