剩余气体分子的束流截面探测器研究

A measurement is important to control the beam width, as well as the transverse matching between different part of an accelerating facility. A profile can be measured by residual gas monitor,where the ionization products of the interaction of the beam with the residual gas atoms or molecules inside the (non-perfect) vacuum of the tube are detected. In these devices the resulting electrons or ions are accelerated by an external electrical field to a detector having a spatial resolution. A profile can also be obtained by the observation of the light emitted by the residual gas molecules excited by the beam interaction. Both are residual gas monitors that measure the beam profile based on interactions with the residual gas in the accelerator beam pipe. They are thus fully noninterceptive devices which allows them to measure profiles at beam intensities at which wire scanner is no longer operational.Beam profile determination at high intensity hadron accelerators implies the usage of non-destructive methods. A system which can make IPM and BIF measurement at same time is built for ADS. Basic requirements for electric and magnetic field are calvulated, the optimized structure of electrode plates and magnets are determined. We desined a system which including electrode plates,MCP,screen and CCD detector, it will can detected the beam profile using the different way.

束流截面测量对于降低束流损失、验证束流光学理论和加速器的调试都有着非常重要的意义。在加速器运行前期，束流的匹配更是保证加速器正常运行必不可少的条件之一。基于加速器管道内剩余气体分子与束流的相互作用原理的截面探测方法有电离型（IPM）与荧光型（BIF）两种。本项目将结合这两种方法，设计一套适用于ADS束流的截面探测装置。通过理论计算电场、磁场以及优化得到IPM系统的设计参数，在此基础上完成包括了引导电极板、微通道板、荧光靶与探测系统在内的机械结构设计，采用荧光靶加CCD相机的探测系统，在腔室一侧开启观察窗，并在管道外加装成像系统即可进行BIF测量，使这一套系统可同时进行IPM与BIF测量。

束流截面测量对于降低束流损失、验证束流光学理论和加速器的调试有着非常重要意义，在运行前期束流匹配更是保证加速器正常运行必不可少的条件之一。强流质子加速器截面测量的一个难点是在不影响束流的情况下测量出束流准确的横向尺寸。最常用的两种截面测量方法荧光靶和丝靶在束流流强较高时均面临着不同的问题，荧光靶会产生大量的次级粒子产生感生放射性，甚至会被高功率的束流损坏，而运动的金属丝靶（有时用碳丝）也面临着散热的问题，也发生过多次丝被束流打断的情况。所以积极开发非拦截式的横向截面测量系统十分重要。特别是现在中国正在积极发展强流加速器，包括在东莞建设的散裂中子源和将来要在惠州开建的加速器驱动的次临界系统ADS，都需要这种新的测量技术。.非拦截式的截面测量主要是基于加速器管道内剩余气体分子与束流的相互作用来测量截面的，主要有电离型（IPM）与荧光型（BIF）两种。本项目将设计适用于ADS 束流的一种截面探测装置。通过理论计算电场、磁场以及优化得到IPM 系统的设计参数，在此基础上完成包括了引导电极板、微通道板、荧光靶与探测系统在内的机械结构设计与加工，采用荧光靶加CCD 相机的探测系统，就能通过束流在经过IPM时与剩余气体分子碰撞产生的气体离子或者电子来得到束流的横向截面测量。下一步在无需改动机械结构的基础之上，在腔室一侧开启观察窗，并在管道外加装成像系统即可进行BIF 测量，使这一套系统可同时进行IPM 与BIF 测量。