Design of a low background mass spectromenter for a high sensitive analytical ion microscope

一个双重质量分光仪的设计被证明是一个高度敏感的分析离子显微镜的同位素分析的固体采样器的一部分。它具有以下能力; （1）约3，200人的高质量分辨率能力;（2）高灵敏度，具有5项强度的宽动态范围;（3）约（+-）0.5%的测量准确性。Matsuda （1983）在《质量光谱学杂志》中计算了“使用质量光谱仪的离子光学参数”。计算结果如下;电场：在凹陷角度上75 °，在粗糙度上40厘米，磁场：在凹陷角度上90 °，在辐射和质量解析功率上20厘米：34002（收集器切片的100微米宽度）。基于这个设计，一个分析器室，一个电子材料，一个电动分析器，它的室被构造成修饰。一个用于蒸发系统的控制电路是设计和定制的，它可以通过接口和连接连接到一台个人计算机。这些是为了测试的真空吸尘器，该系统被认为是一种最大的压力，可以被发现大约1X 10^<-7>没有任何烤室的火炬。就像一个电磁场和磁场一样，可以在极点碎片的范围内扫描到0-5000高斯。这个范围对应于0-250的质量范围，在2千伏的离子加速电压下，因此，这个双重聚焦的质量光谱仪可以用作高度敏感的分析离子显微镜的探测器。

The design of a double fousing mass spcectrometer has been attempted as a part of a highly sensitive analytical ion microscope for the isotope analysis of solid samplesd. It has the follwoing capabilities; (1) high mass resolbing power of about 3200, (2) high sensitivity with a wide dynamic range of 5 orders of magnitude and (3) high accuracy of measurement of about (+-)0.5%. We calcuated the ion optical parameters of the mass spectrometer using "the program for a personal computer" by Matsuda (1983) in the journal of Mass Spectroscopy. The results of the calculation is as follows; electric field: 75゜ in deflection angle and 40cm in rafidus, magnetic field: 90゜ in deflection angle and 20cm in radius and mass resolving power: 3400 2( 100um width of a collector slit. Based on this design, An analyzer chamber, an electro-matnet, a momwntum analyzer and its chamber wete constructed. A controlling circuit for evacuation system has been designed and consttucted, this can be connected to a personal computer through an interface and relays.These were tested for vaclum and the ultimate pressure of the system ha benn attained to be about 1 X 10^<-7> Torr without any baking of the chambe. As for an electro-magnet, magnetic field at the cenger of of pole pieces was found to be able to sweep over the trange 0-5000 Gauss. This range corresponds to the mass range of 0-250 at an ion accelecrating voltage of 2kV.Therfore, this double focusing mass spectrometer can be used as a detector of a highly sensitive analytical ion microscope.