Study on baking deformation of the thin-walled arc chamber

Abstract

A large scientific facility, High Intensity heavy-ion Accelerator Facility (HIAF), was being built to study basic and interdisciplinary sciences. To meet the requirements of magnetic rigidity for high-energy heavy ions, pulsed dipole magnets were used in Booster Ring (BRing). Therefore, the ceramic-lined thin-walled arc chambers with 0.3 mm shell were developed to reduce the eddy current resulting from the rapidly changing magnetic field. Furthermore, to satisfy the requirements of the beam lifetime, the pressure of BRing of the HIAF must be lower than 1 × 10−9 Pa. In-situ baking methods were used to obtain ultra-high vacuum. As the stiffness of the thin-walled arc chamber was poorer for evacuation and in-situ baking as a conventional way, it had to be controlled in the deformation and deflection angle. Thus, a deformation control method using springs was adopted. The results show that the longitudinal deformation of both different thin-walled chambers was controlled to within 0.3 mm, the radial deformation was controlled to within 0.8 mm and the variation of deflection angle was within 0.2°.