BEPC对撞区真空系统改进

Improvement of vacuum system for BEPC interaction region

BEPC对撞区真空系统是储存环真空系统中最重要的部分之一 ,对撞区真空系统的性能直接影响着用于高能物理实验的谱仪探测器的本底 ,因此提高对撞区的真空度非常重要。本文提出了在靠近对撞点的附近安装 NEG泵用于提高对撞区真空度的方案 ,并且用经典的数学计算方法和蒙特卡洛模拟计算方法预测了安装 NEG泵的效果 ,同时在实验中证明了通过 NEG泵改善对撞区真空度的可行性。通过对 BEPC对撞区真空系统的改进 ,使 BEPC对撞区静态压强由原来的 8× 10 - 8Pa下降到 2 .7× 10 - 8Pa。

BEPC Interaction Region (IR) vacuum system is one of the most important parts in storage ring vacuum system, the performance of IR vacuum system affects directly the background of spectrometer detectors for the high energy physics experiments, therefore it is very significant to improve IR vacuum degree. This paper puts forward the methods which are used to improve the vacuum degree of IR vacuum system by installing NEG pumps near the colliding point, and predicts the affects of installing NEG pump in IR vacuum system through calculation methods of both classic mathematics and Monte carlo simulation. In the meantime, the feasibility of improving IR vacuum degree by NEG pump in the experiments is proved. By the improvements for BEPC IR vacuum system, static pressure of BEPC IR has decreased from initial value of 8×10 -8 Pa to 2.7×10 -8 Pa.