上海质子治疗装置同步环真空布局及真空室设计

Vacuum Layout and Chamber Design for Synchrotron Ring of Shanghai Proton Therapy Facility

同步环是上海质子治疗装置的主要加速器,其周长为24.6m。环上各系统器件分布密集,机械安装空间紧张,动态真空度要优于1.33×10^(-6) Pa。在此前提下,真空器件布局和真空室结构要利于束流的均匀性、稳定性,并确保机械安装顺利以及将来运行维护便利。针对同步环物理布局紧凑的特点,真空布局上真空室尽量采用焊接连接,在满足要求的前提下尽量减少真空器件数量。二极铁(BM铁)区段真空室采用矩形截面结构,四极铁(QD铁、QF铁)区段真空室采用圆管结构,相邻的矩形真空室和圆管真空室用过渡片焊接成一整体;束流引出区段真空室采用变截面岔口结构。设计结果表明,真空布局和真空室结构均满足束流的运行要求。

Synchrotron ring with 24.6 m circumference is main accelerator in Shanghai Proton Therapy Facility. The space for mechanical operation in the ring is very narrow because of many components. The vacuum for synchrotron ring need be better than 1.33 × 10^-6 Pa. The requirement to vacuum components layout and chamber structure is to contribute to beam uniformity and stability, and to facilitate mechanical assembly. To meet the lattice, vacuum chambers were connected by welding as possible, and the amounts of vacuum components were minimized. The cross section of chamber in BM was rectangular, and in QD and QF was circular. Rectangular chamber and circular chamber were welded by a transitional plate. The chamber in beam splitting region was designed as a fork structure with variable section. The design result shows that the vacuum layout and chamber structure can meet the need of beam running.