合肥光源托歇克效应损失电子的探测

Detection of electron loss due to Touschek effect in Hefei Light Source

束流寿命是衡量储存环性能的重要参数,直接影响着光源的正常运行。对于合肥光源(HLS),托歇克(Touschek)寿命是影响束流寿命的重要因素。为了研究Touschek寿命,需要探测由于Touschek效应所损失的电子。介绍了束流寿命的概念,说明了Touschek效应的原理和机制,利用蒙特卡罗软件EGSnrc模拟计算了丢失电子与真空壁的相互作用,通过塑料闪烁体探测器和光电倍增管获得了由于Touschek效应丢失的电子所产生的信号,然后将信号经过放大甄别和符合处理后,用计数器测量了计数率。结果表明:由于Touschek效应而成对丢失的电子的确存在,且电子损失率随流强的降低而减小。这为下一步储存环的能量标定工作做好了前期准备。

The beam lifetime is an important parameter which can affect the operation of the storage ring.For Hefei Light Source（HLS）,Touschek lifetime is an important factor affecting beam lifetime.To study the Touschek lifetime,the loss of electrons due to the Touschek effect should be detected.The concept of beam lifetime is introduced,and the theory of the Touschek effect is also discussed.The interaction between the lost electrons and vacuum chamber wall is simulated by the Monte Carlo software EGSnrc.The signals of the electron loss due to the Touschek effect are obtained with the plastic scintillation detector and then,sent to the discriminator and the coincidence gate,and finally the count rate is measured with a counter.The results indicate that the loss of electrons due to the Touschek effect does exist,and the loss ratio decreases with the reduction of the beam current.