Alumina ceramics vacuum duct for the 3GeV-RCS of the J-PARC

Kinsho, Michikazu  ; Ogiwara, Norio; Saito, Yoshio*; Kabeya, Zenzaburo*

It was success to develop alumina ceramics vacuum ducts for the 3GeV-RCS of J-PARC at JAERI. There are two types of alumina ceramics vacuum ducts needed, one being 1.5m-long duct with a circular cross section for use in the quadrupole magnet, the other being 3.5m-long and bending 15 degrees, with a race-track cross section for use in the dipole magnet. These ducts could be manufactured by joining several duct segments of 0.5-0.8 m in length by brazing. The alumina ceramics ducts have copper stripes on the outside surface of the ducts to reduce the duct impedance. In order to reduce emission of secondary electrons when protons or electrons strike the surface, TiN film is coated on the inside surface of the ducts.