JPH0437400B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to an aging control method for an electron beam irradiation device that performs aging of the electron beam irradiation device, and an object of the present invention is to enable aging of the electron beam irradiation device to be performed automatically and appropriately. shall be.

Conventionally, when aging an electron beam irradiation device, the inside of the acceleration tube and scanning tube of the electron beam irradiation device are evacuated, and the operator reads the degree of vacuum inside both tubes as indicated by a vacuum gauge. Aging is performed by an operator controlling the electron accelerating voltage in the accelerating tube and the heating power of the filament that emits electrons, depending on the degree of vacuum in both tubes.

However, in the above case, aging may take a long time of one to several days, and reading errors are likely to occur when the operator reads the vacuum gauge display, and these errors may cause the acceleration voltage, etc. to be optimized. The disadvantage is that the value cannot be controlled. In addition, because the operator does not read the vacuum gauge display all the time, but only at certain intervals, the operator is unaware of the deterioration of the vacuum inside the accelerating tube and scanning tube, causing electrical discharge to occur inside the accelerating tube. Such problems may occur.

This invention has been made with the above-mentioned points in mind, and includes evacuating the inside of an acceleration tube and a scanning tube of an electron beam irradiation device and detecting the degree of vacuum inside both tubes by means of a vacuum degree detection means. The detection signal of the detection means is input to an acceleration voltage control system to control the electron acceleration voltage according to the degree of vacuum, and after the acceleration voltage reaches a predetermined value, the acceleration voltage is held constant and the detection signal is controlled. is input into an electron flow control system, and in this state, the heating power of the filament is controlled according to the degree of vacuum, thereby controlling the heating power of the filament to a final predetermined value. The present invention provides an aging control method.

Therefore, according to the aging control method for an electron beam irradiation apparatus of the present invention, the electron acceleration voltage and the filament heating power are sequentially controlled to predetermined values based on the detection signal from the vacuum degree detection means while evacuation is being performed. Since the aging of the electron beam irradiation device is performed using two-step control, control becomes simple, aging can be performed quickly, and automation can be achieved.

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

In the drawing, 1 is an electron beam irradiation device consisting of an acceleration tube that accelerates electrons emitted from a heated filament, a scanning tube that scans the accelerated electron flow, etc., and 2 is an electron beam irradiation device that detects the degree of vacuum of the acceleration tube and scanning tube. 3 is an acceleration voltage control system that outputs a voltage control signal to control the voltage applied to the electrodes disposed in the acceleration tube, that is, the electron acceleration voltage; 4 is an electron An electron flow control system 5 outputs a flow control signal to control the heating power of the filament to control the electron flow from the filament; 5, the first and second contacts 6 and 7 are connected to the acceleration voltage control system 3 and the electron flow, respectively; It is a changeover switch connected to each input end of the control system 4, and the changeover piece 8 is connected to the output end of the vacuum level detection means 2, and the detection signal from the vacuum degree detection means 2 is passed through the changeover switch 5. It is input to an acceleration voltage control system 3 and an electron flow control system 4.

When aging the electron beam irradiation device 1, the inside of the acceleration tube and the scanning tube are started to be evacuated by a vacuum pump or the like, and the degree of vacuum inside the tubes is started to be detected by the degree of vacuum detection means 2. When the degree of vacuum becomes better than a predetermined value, application of voltage to the electrodes in the acceleration tube is started.

That is, at first, the changeover piece 8 of the changeover switch 5 is connected to the first contact 6, and the detection signal output from the vacuum degree detection means 2 based on the degree of vacuum detected by the degree of vacuum detection means 2 is connected to the changeover switch 5. The acceleration voltage control system 3 controls the voltage applied to the electrodes of the acceleration tube according to the degree of vacuum inside the acceleration tube and scanning tube based on the detection signal, and also controls the voltage applied to the electrodes of the acceleration tube. While controlling the applied voltage according to voltage fluctuations, the applied voltage is gradually increased until it reaches a predetermined value, and when the applied voltage reaches the predetermined value, the applied voltage is held constant.

Next, while maintaining the voltage applied to the electrodes of the accelerator tube at a predetermined value, the switching piece 8 of the switching switch 5 is connected to the second contact 7, and the detection signal from the degree of vacuum detection means 2 is transferred to the switching switch 5. Similarly to controlling the voltage applied to the electrodes of the accelerating tube, the heating power of the filament is determined according to the degree of vacuum inside the accelerating tube and scanning tube based on the detection signal. By controlling to this value, aging of the electron beam irradiation device 1 is completed.

The voltage applied to the electrodes of the accelerating tube and the heating power for the filament are controlled by controlling the degree of vacuum that changes over time, as shown in curve A in FIG. When the preset levels a and b are below a, between a and b, and above b, the heating power of the filament is increased, maintained, and decreased, respectively, as shown by curve B in the same figure. The heating power is finally controlled to a predetermined value under a predetermined degree of vacuum, and the applied voltage is also controlled in a similar manner.

Therefore, according to the embodiment, the degree of vacuum inside the acceleration tube and the scanning tube of the electron beam irradiation device 1 is detected by the degree of vacuum detection means 2 while being evacuated. The signal is output to the accelerating voltage control system 3, and the voltage applied to the electrodes of the accelerating tube is controlled according to the degree of vacuum using the detection signal and held at a predetermined value. In this state, the changeover switch 5 is switched to detect the degree of vacuum. The aging of the electron beam irradiation device 1 is reduced by inputting the detection signal from the means 2 into the electron flow control system 4 and controlling the filament heating power to a final predetermined value according to the degree of vacuum using the detection signal. It can be done automatically with step-by-step control.
There is no need for workers to be on standby as in the past, and aging can be performed quickly with simple control.

Note that the control may be performed taking into account the rate of change in the degree of vacuum.

[Brief explanation of drawings]

The drawings show one embodiment of the aging control method for an electron beam irradiation apparatus according to the present invention, and FIG. 1 is a block diagram, and FIG. 2 is a diagram showing the relationship between filament heating power, degree of vacuum, and time in aging control. be. 1... Electron beam irradiation device, 2... Vacuum degree detection means, 3
...acceleration voltage control system, 4...electron flow control system.

Claims (1)

[Scope of Claims] 1. While evacuating the inside of an acceleration tube and a scanning tube of an electron beam irradiation device, the degree of vacuum in both tubes is detected by a degree of vacuum detection means, and the detection signal of the detection means is first transmitted to an acceleration voltage control system. control the electron acceleration voltage according to the degree of vacuum, and after the acceleration voltage reaches a predetermined value, maintain the acceleration voltage constant and input the detection signal to the electron flow control system. 1. An aging control method for an electron beam irradiation apparatus, comprising: controlling the heating power of the filament according to the degree of vacuum in the state, thereby controlling the heating power of the filament to a final predetermined value.