Paper VT-TuM5
Newly Designed Alumina Ceramics Beam Pipe with Large Aperture for RCS in J-PARC

Tuesday, October 31, 2017, 9:20 am, Room 7 & 8

The 3 GeV Rapid Cycling Synchrotron (RCS) in J-PARC aims to generate one of the highest power protons in the world. The design extraction beam power is 1 MW, which consists of 8.3 × 10¹³ protons per bunch with 3 GeV energy at 25 Hz repetition rate. The rapid change of the magnetic field at such repetition rate causes the induced current if the beam pipe was made of metal. Therefore, beam pipes of alumina ceramics were used. The cross-sectional diameters of the pipes range from 250 to 500 mm, as is the case for the titanium beam pipes and bellows. There are several cross-sectional shapes corresponding to the various beam shapes. The beam pipes in the dipole and quadrupole/sextupole magnets have racetrack and circular shapes, respectively. The beam pipes in injection magnets have racetrack and rectangular shapes. Unique cross-sectional shape is adopted for the ceramics beam pipes for the injection quadrupole magnet. Because the injection beam and circulating beam pass through the injection quadrupole magnet, its cross-section has a racket shape fitting into 500 mm diameter. Recently this ceramics pipes for the injection quadrupole magnets were newly designed. In the new design, the bellows are attached to the titanium sleeve of the beam pipe by welding to obtain the better maintainability in the narrow area under high radioactivation level. In the conference, we will report the design concept of the new alumina ceramics beam pipes with unique shape and the several results of the verification tests.