Design And Realization Of HR-SIMS Vacuum Measurement And Control System

High Resolution Secondary Ion Mass Spectrometer（HR-SIMS）is the most advanced sample surface analysis instrument with high spatial resolution,high mass resolution and high sensitivity.It is used in semiconductor,ocean and Mineral resources,new energy,nuclear industry,space science and life science are indispensable in fields related to national economy and national defense security.The HR-SIMS instrument must work in a high vacuum environment,and the vacuum pressure has a great influence on the ion output rate and ion flight trajectory.Relying on the"Research and Development of High-Resolution Secondary Ion Mass Spectrometer"project of the Institute of Oceanology,Chinese Academy of Sciences,this paper builds a vacuum platform and develops a supporting vacuum measurement and control system for the needs of HR-SIMS.The main work is as follows:（1）Based on the theoretical basis of HR-SIMS instrument vacuum system,theoretically calculate the selection of vacuum equipment,and build an instrument vacuum platform;study the functional requirements of the instrument vacuum measurement and control system,formulate the overall plan of the vacuum measurement and control system,and use the ARCNET bus based on optical fiber,and adopts the structure of hub and distributed controller,which has the characteristics of reliability,high fault tolerance and easy expansion.（2）Develop HR-SIMS vacuum measurement and control system hardware device,design the hardware circuit of the hub and 6 distributed vacuum equipment controllers,including the peripheral circuit unit of the main control chip,communication unit,ARCNET LAN communication circuit,optical fiber transceiver circuit,relay switch control circuit,etc.（3）Design HR-SIMS vacuum measurement and control system software,including lower computer software and upper computer human-computer interaction software.The design of the lower computer adopts a modular development idea,and the program design is carried out in units of functions,which is convenient for debugging one by one and calling the main program;the upper computer is developed based on LabVIEW,and realizes the functions of vacuum equipment control and detection;for the instrument that may be caused by vacuum In order to avoid the risk of damage to instrument components due to leakage,a vacuum interlock protection mechanism was studied.（4）The performance of the built vacuum system platform and the function of the vacuum measurement and control system are tested.The main interface of the measurement and control system can display the vacuum value of each cavity,the vacuum value of the backing pump pipeline and the status and operation information of the main pump and the backing pump in real time,and can realize the reading and control of the vacuum degree of the vacuum equipment;it can realize the automatic pumping of the chamber Gas,air intake and other processes;the pressure monitoring screen interface can correctly display the vacuum degree of each section cavity and the vacuum degree of the backing pump pipeline,and the software and hardware functions of the measurement and control system can be realized.The vacuum system platform actually tested the vacuum of the ion source chamber and the primary ion optical system chamber to be 7.00×10^-9Torr,and the vacuum of the source chamber and the sample lock chamber was 7.00×10^-9Torr,the vacuum degree of the electrostatic analyzer cavity is 3.80×10^-8 Torr,and the vacuum degree of the receiver cavity is 1.87×10^-8Torr,which can better meet the index value.