正电子直线加速器俘获节加速场梯度对俘获率的影响

HOW THE ACCELERATING GRADIENT OF THE CAPTURE SECTION TO EFFECT ON THE CAPTURE RATE IN THE POSITRON LINAC

一、引言在正电子直线加速器中,正电子在靶上生成,经过一段匹配段,进入加速管。通常称这根加速管为俘获节。俘获节的加速场梯度如何影响正电子的俘获率,是在加速器设计和运行过程中很感兴趣的一个问题。所谓俘获,指的是,粒子在横向不碰到系统管壁,在纵向聚到一定相位范围,且在俘获节末端的能散度不超过某个限度。这样,正电子在以后的加速过程中,一定相宽内粒子数的多少将决定最终束流能谱的好坏。

In the paper, It is calculated that the accelerating gradient of the capturesection how to effect on the capture rate in a positron linac, and the result isused to compare with the measurement value of the BEPC. It is indicated thathow wide is the region in which the capture rate is independent on the accelera-ting gradient, and why pursuing the higher gradient is still significant.