The Design And Experimental Study On High-Voltage Floating Gate-Controlled Power Of Electronic Linac

In the electronic industry of irradiation, the core equipment is electronic linac.Electronic irradiation is the thing that uses high-energy electrons to deal with class ofobjects in order to achieve specific goals in the process. In the electronic irradiation,the high-energy electrons are used to the irradiated material in order to achievesterilization, degradation of harmful substances, change the nature of the material andpreparation of new materials.The design of the gated-gun is generally on the basis of the two-pole gun design,add a control pole (gate). When coupled with a suitable voltage between the cathodeand the gate (the Potential of the gate is negative to the cathode). It can stop thecathode emitting electrons. Adjusting the voltage can control the flow of electrons.The structure of the three-pole gun is developed on the basis of the two-pole gun, so ithas a more chance for development. Relative to the two-pole gun, the most importantand most significant change in the structure of the three-pole gun is add anothercontrol pole. It can be foreseen that for a longer period of time, the study of theelectrical linac gate-control power will become the research focus. So thedevelopment of gate-control power with good performance is very important in theelectrical linac system.Involved works in this thesis are combinations of electrical linac gated-controlpower project in Shandong Vanform Group. The main purpose of this thesis is todesign and study an electrical linac gated-control power, and to meet the requirementsof the actual production and use. Generally, the structure of the designed gated-controlpower is divided into two parts, one part is gated-control circuit which is floating onthe60KV, and the other is communication circuit which is connected to thegated-control part with optical fiber. The gated-control circuit adjusts the voltage to control the flow of the electrons. The communication circuit has three roles, one todisplay the main circuit voltage and current values, the second is to adjust the maincircuit, so that the gate voltage value in the ideal range and the third is to protect thegated-control circuit. These two circuits are located in two different PCB The logicallocation of the gated-control circuit is located between the cathode and the gate. Thephysical location is located near the appropriate location of the electrical linac. Thelogical location of communication circuit is between the gated-control circuit and theconsole. The physical location is in the power-cabinet.The gated-control circuit triggers and adjusts the output voltage when it receivesthe orders from the communication circuit. The gate control circuit is broadly dividedinto five parts, namely: the main circuit, voltage regulator signal receiving part, pulsetrigger signal receiving part, the current sampling part, the voltage sampling part andthe power supply part. The thesis explains these parts in detail.The communication circuit sends the voltage regulator and trigger signal togated-control circuit and receive the signal from the gated-control circuit to show thevoltage and current. According to the designed goals, the communication circuit isroughly divided into four parts, namely: sampling the signal to display part, theregulator signal sending part, over-voltage and under-voltage protection part andpower supply part. The thesis explains these parts in detail.The gated-control circuit exist VFC and the communication circuit exist FVC.The role of these circuits is easy to show the state of these circuits to the staff. Thesecircuits play an important role in the whole design. So before drawing PCB, I do someexperiments to ensure the functions of the voltage-frequency conversion circuit, thefrequency-voltage conversion circuit, electro-optical conversion circuit andoptical-electro circuit. The experimental results meet the design objectives.After designing the circuit, draw the PCBs according to the circuit.At the last, do the verification experiments of these circuits. After the completionof each part’s verification experiment, debug these two circuits together. Through theactual experiment, we can verify the function of these circuits. All of the experiment shows that in all aspects the output parameter of the designed gated-control power canmeet the target goal.