JPS6230400B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electron beam irradiation device.

As is well known, this type of irradiation device requires, in addition to the accelerating tube, a DC high voltage power source for acceleration and a power source for heating the filament. Since the power source for heating the filament must have the same or almost the same potential as the high voltage generated by the DC high voltage power source, it is usually provided at a high voltage site with sufficient insulation from the ground.

Conventional power supplies for heating this kind of filament include those using an isolation transformer, generators installed in high potential parts (e.g. magnet generators), voltage regulators (e.g. thyristors, magnetic amplifiers, sliders). etc.) and signal transmission paths (e.g., insulated shafts, optical transmission paths), step-down transformers installed on the high voltage output side of DC high voltage power supplies,
Some are composed of a voltage regulator and a signal transmission path.

However, the above method is bulky and the entire device of this type is expensive. Furthermore, since so-called electronic components such as semiconductors are disposed in high-voltage areas, these components may be destroyed by surge voltage, and this type of device lacks reliability.

The object of the present invention is to make the power source configuration for heating the filament and its control configuration as simple and inexpensive as possible, and to obtain a highly reliable one without using electronic components.

In this invention, only a generator and a filament transformer are installed in a high voltage part, and the heating of the filament is controlled by controlling the rotational speed of an electric motor connected to the generator through an insulated shaft. It is characterized by

Embodiments of this invention will be described with reference to the drawings: 1
2 is a DC high voltage power supply, 2 is an accelerating tube, and 3 is a filament of the accelerating tube 2. The DC high voltage power supply 1 may have various known configurations. The illustrated configuration is a Kotscroft-Walton type voltage doubler rectifier circuit, and the transformer 4 includes a plurality of capacitors 5 and a plurality of rectifiers 6. The obtained DC high voltage is then applied to the filament 3.

According to the present invention, a generator 7 such as a magnet generator is provided at a high voltage portion of the DC high voltage power supply 1, and the generator 7 and the filament 3 are connected via a filament transformer 8. Then, an electric motor 9 is installed on the ground or at a low voltage site, and this electric motor 9
and the generator 7 are connected by an insulating shaft 14. Therefore, the driving force of the electric motor 9 is applied to the generator 7 via the insulated shaft 14, and the generator 7 generates a voltage according to its rotation speed, and supplies heating power to the filament 3.

By the way, the electrons emitted from the filament 3 become a so-called electron flow, and as shown by the dotted line I _B in the figure, they reach the DC high voltage power supply 1 side via the ground, but in this case, there are electrons between the power supply 1 and the ground. By providing the flow detector 10, it becomes possible to detect the electron flow. This detector 10 outputs a detection voltage signal Vf corresponding to the detected electron flow. 1
1 is a setting device for setting the electron flow to a desired value, and outputs a setting voltage signal Vs. 12 is a amplifier,
Error amplification is performed on both voltage signals Vf and Vs, and an output signal is output to the rotation control circuit 13. This rotation control circuit 13 sets the voltage and frequency applied to the electric motor 9 in order to control the rotation speed of the electric motor 9. It goes without saying that the setting device 11, the amplifier 12, and the rotation control circuit 13 are provided in a low voltage region.

In this structure, the amount of electrons emitted from the filament 3 is detected as an electron flow rate by the electron flow detector 10, and a detected voltage signal Vf corresponding to the detected amount is obtained. On the other hand, since the set voltage signal Vs for setting the desired electron flow is output from the setter 11, the error of both signals Vf and Vs is amplified by the amplifier 12, and the rotation control circuit 13 is Through this, the rotation speed of the electric motor 9 can be controlled. On the other hand, the rotation speed of the generator 7 is increased or decreased in accordance with that of the electric motor 9. As a result, the output voltage of the generator 7 is controlled from the low voltage section, and the heating power supplied to the filament 3 can be freely controlled at the low voltage section. In this way, the electron flow from the filament 3 is controlled according to the value set in the setting device 11.

In the illustrated example, the DC high-voltage power supply 1 is composed of a Kotscroft-Walton type voltage doubler rectifier circuit. It may be something.

As detailed above, according to the present invention, it is no longer necessary to use an isolation transformer as in the past for heating and controlling the filament of an accelerator, or to use electronic components in high voltage parts. Since there are no holes, the structure can be simplified, this type of device can be made inexpensive, and a highly reliable device can be obtained. Furthermore, according to the present invention, heating control of the filament can be performed at a low voltage section, so that control and handling are extremely easy. This drives the generator via the insulated shaft, so
Its output voltage can be precisely adjusted to any value,
Therefore, the electron flow from the filament can be adjusted to a desired value with high precision.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of the invention. 1... DC high voltage power supply, 2... Accelerator tube, 3... Filament, 7... Generator, 9... Electric motor, 14... Insulated shaft.

Claims (1)

[Claims] 1. A DC high-voltage power supply, an acceleration tube to which a high voltage is applied from the DC high-voltage power supply, a generator installed in a high-voltage area and supplying heating power to the filament of the acceleration tube via a filament transformer, and a low-voltage generator. an electric motor connected to the generator through an insulated shaft, and an electric signal corresponding to the electron flow emitted from the filament in the low voltage region, and a preset desired electron flow. The heating control of the filament is performed by amplifying the error of the electric signal corresponding to the electric signal, thereby setting the voltage and frequency applied to the electric motor, and controlling the rotation speed thereof. Electron beam irradiation equipment.