Development of a Precise Sample Position Control Device for Beam ExPeriments

利用超高压步进电机、滑动轴承和滚珠丝杠，构成了一种用于分子束或离子束散射实验的精密可控机械手。机械手和超高压铝真空容器的机械部分在我所机械车间建造，电子部分由我所实验室制备。该机械手具有X、Y、Z、θ、φ、倾角六个自由度，可控制样品相对于光轴的位置。样品的移动范围<plus-minus>为XY轴22mm，<plus-minus>Z轴12mm，<plus-minus>倾斜度7 μ m，reta和phi均为360 μ m，样品交换的垂直移动范围为830mm。完成了（X，Y，Z，rheta）轴的移动测试，没有任何问题。其他动作正在测试中。真空测试是通过具有碳分子泵、离子泵和旋转泵的组合的泵送系统进行的。在泵送的初始阶段，释放了大量的气体，但是在几个烘烤循环之后，真空压力达到10 μ <-9>Torr。为了检查真空的质量，我们用四极质谱仪分析了残余气体。除H_2、H_2O、CO、CO_2等常见的残余气体成分外，还检测到一些碳氢化合物和氯化氢分子。起源尚不清楚。其他问题是在运动过程中从轴承中排出的气体和运行中电机温度的升高。这些问题应在不久的将来得到解决。

A precisely controlable manipulator for use in molecular or ion beam scattering experiments was constructed by using uhv stepping motors, slide bearings and ball screws. The mechanical parts of the manipulator and the uhv aluminum vacuum container were constructed in the mechanical workshop of our institute, and the electronic parts were prepared by our laboratory. The movement test of the stages etc. By a personal computer and the vacuum test were also done in our laboratory.The manipulator can control the sample position against the beam axis with six freedoms of ( X, Y, Z, rheta, phi, inclinatin ). The moving ranges of the sample were <plus-minus>22mm for the XY axis, <plus-minus>12mm for the Z axis, <plus-minus>7^ﾟ for the inclination, 360^ﾟ for both rheta and phi, and 830mm for vertical movement for sample exchange. The movement test for ( X, Y, Z, rheta) axis was finished without any problems. The other movements were now under testing. The vacuum test was carried out by a pumping system with a combination of a tarbo-molecular pump, an ion pump and a rotary pump. In the initial stage of pumping a large amount of gas was released, but the vacuum pressure reached into 10^<-9> Torr after several cycles of baking. In order to check the quality of the vacuum we analyzed the residual gas with a quadruple mass spectrometer. Some hydrocarbons and hydrogen chloride molecules in addition to the usual residual gas components (H_2, H_2O, CO, CO_2 ) were detected. The origin is unclear. Other problems are the outgas from the bearings during the motion and the increasing of temperature of the motor in operation. These problems should be solved in near future.