强流重离子加速器运行时产生动态真空效应引起束流寿命缩短,需安装无氧铜束流准直器来降低该效应.为探究无氧铜材料在离子束轰击下的解吸性能,本工作设计并研制了满足低温工况的解吸率测试装置,在兰州重离子加速器国家实验室利用Xe23+离子束完成了无氧铜温度在4.2 K、20 K、77 K和300 K,以及束流能量为0.58 MeV/u、0.96 MeV/u和1.3 MeV/u的在束试验.结果表明,离子束轰击无氧铜表面时解吸出最多的分子为H2,其次分别为H2O、CO、CO2、Ar和O2;当温度为4.2K、束流能量为0.58 MeV/u时无氧铜解吸出H2的比例为87.74%.在同一能量下,随着无氧铜表面温度的升高,解吸率呈增加趋势,能量为0.58 MeV/u时,4.2 K下无氧铜的解吸率仅为25 moVion,小于300 K时的600 mol/ion,表明温度越高其解吸产额越大.在同一温度下,随着束流能量的升高无氧铜表面解吸率增加,但增加趋势逐渐减缓,解吸产额趋向饱和.
The dynamic vacuum effect during the operation of high intensity heavy-ion accelerator facility,which destroys ultra-high vacuum stable envi-ronment and causes the beam lifetime to decrease.It is necessary to install an oxygen-free copper collimator to minimizing the dynamic va-cuum effect.To research the desorption yields of oxygen-free copper under different temperature conditions,a low temperature desorption yields test system was developed.Beam experiments of oxygen-free copper at 4.2 K,20 K,77 K and 300 K were competed in Lanzhou Heavy Ion Ac-celerator National Laboratory using continuous Xe23+ions with 0.58 MeV/u,0.96 MeV/u and 1.3 MeV/u.The result showed that the main de-sorbed molecule was H2,and followed by H2O,CO,CO2,Ar and O2 under the beam bombarded oxygen-free copper conditions.Besides,the proportion of oxygen-free copper desorbed H2 was 87.74%when the temperature was 4.2 K and the energy was 0.58 MeV/u.At the same ener-gy,the desorption yields were increased gradually with the oxygen-free copper temperature rising.The desorption yield of oxygen-free copper was only 25 mol/ion at 4.2 K and 0.58 MeV/u,which was less than 600 mol/ion at 300 K,indicating that the higher oxygen-free copper tempera-ture,the greater the desorption yield.At the same temperature,the desorption yields were increased with the increasing of beam energy,but the trend slow down and the desorption yields tends to be saturated.