Studies About Control System Of Linac

Part II joined in the work about the control system of linac, include:the computer control system、 the control circuit of the electron gun and the Bean current monitor. The computer control system developed by us is made up of:PLC controller, control workstation and communication device.The control interface is developed in STEP7and C. The advantage of the system is:Good generality, better reliability, powerful. The control circuit of the electron gun we developed is made up of:alternating current power circuit, adjustable circuit and EUV module.It can stabilize the current by control the voltage of the gun’s heater. Meanwhile, the stability and safety of the control circuit is guaranteed. Feedback circuit can control the electron’s launching of the gun, and stabilize the launching. The Bean current monitor we developed is made up of:Back-placement amplifier, integral amplifier and monitor. The signal from detection system is transformed to digital value finally, and shown by Digital Table. Compared with other similar system, the adventure of our system is: convenient, using easily, better stability.Part II Optical fiber sensor can be used as a way to measure the current of the electron beam in linac. Two optical fiber sensor using an in-line wire metal grating (WMG) polarizer are proposed. The WMG is fabricated on the tip of a standard single mode fiber (SMF) at1550nm wavelength by focused ion beam (FIB) technology. The metal used is Au and period of the grating is200nm, far smaller than the wavelength of incident light. The transmission light entering the structure is polarization according to the effective medium theory (EMT).The reflection contrast between TE and TM modes in our experiment reaches13.7dB, which is sensitive enough to monitor the polarization change induced by photoelastic effect and Faraday effect. Based on this WMG grating, a pressure sensor with the sensitivity of0.237rad/N and a current senor with the sensitivity of0.06022degree/A are presented.