高均匀度、大束斑束流线设计

Design of high uniformity,large spot beam line

为满足放射性核素生产及科研的需求,中国原子能科学研究院设计了一台可加速H-与D-离子,双向剥离引出最高能量为70MeV的质子束或者35MeV的D束的紧凑型回旋加速器及配套束流输运系统。设计要求靶上束斑直径40mm,均匀度好于95%,靶后180mm范围内束流包络变化小于±1%以提高放射性核素的生产效率、延长靶的使用寿命。为此设计了旋转扫描磁铁,利用周期旋转的垂直于束流方向的二极场使束流在靶上进行扫描以达到均匀化。在考虑了光学匹配过程中引出区主磁铁的边缘场以及引出开关磁铁带来的色散效应的基础上研究了粒子在靶上的分布,并使束流在靶上成腰。

A compact cyclotron and its beam line system have been designed at China Institute of Atomic Energy to do the i- sotope production and the scientific research. The cyclotron is able to deliver proton beams with an energy in the range 35 - 70 MeV and deuteron beams with an energy in a range of about 18-33 MeV. The extraction beam line is to be equipped with a prop er device which is able to produce a circular beam spot with 40 mm diameter and a spot transverse dimension variation of ver a length of 180 mm and with an intensity uniformity better than 95G to improve the efficiency of the isotope production and prolong the lifetime of the target. The wobbling magnet has been designed to let beam scan on the target to get the beam current density uniformity. The particle distribution on the target is studied under the dispersion study caused by the fringe field and the field of the combination magnet, the beam will be the waist at the target.