JPS5840816B2 - Gas insulated X-ray tube equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to x-ray tube devices, and more particularly to gas-insulated x-ray tube devices.

An X-ray tube is basically a diode tube with an anode and an anode, and electrons emitted from the anode are accelerated by the potential difference between the anodes and collide with the anode to generate X-rays. Since most of the heat is converted into heat, treatment of this heat is extremely important in practical terms.

The present invention relates to this heat treatment. Since X-ray tubes are used at high voltages, they are usually housed in an electrically shielded container (called a Haube) and insulated.

A solid support is used to hold the X-ray tube in the container, but the parts other than the supported parts are surrounded by liquid or gas insulators to improve cooling.

Insulating oil and sulfur hexafluoride (hereinafter represented by the chemical formula SF6) are generally used.

) is used. Gas insulation
Although it is called a wire tube device, its feature is that it can be lightweight.
It is mainly used as a portable type in combination with a sealed X-ray tube.

When insulation is performed with gas, the disadvantage is that gas has a low specific heat and thermal conductivity, so it is generally not possible to provide sufficient cooling. A passage through which a cooling liquid passes is provided in the anode and liquid cooling is performed using water or oil.

However, in this case, the structure of the anode is extremely complicated, and a powerful pump system is required to circulate a sufficient amount of cooling liquid.

The present invention has a simple structure and high load capacity.
It is possible to obtain a wire tube device, and its feature is that a refrigerant, which is an insulator in both liquid and gas states, is sprayed onto the anode member, and the anode is cooled by the heat of vaporization when this refrigerant vaporizes. It's about letting people know.

Embodiments of the present invention will be described below with reference to the drawings.

Note that the same parts are denoted by the same reference numerals 6. FIG. 1 shows an example in which the present invention is applied to a sealed rotary anode X-ray tube that does not have an evacuation system.

The X-ray tube has a glass vacuum envelope 11 and a heat-resistant alloy anode 12.
and an anode 13 are vacuum-tightly sealed.

A tungsten alloy target 14 is attached to the surface of the anode, and an electron gun 15 is provided at the tip of the anode.

The X-ray tube is rotatably held in an X-ray tube storage container 16 made of aluminum alloy and lined with lead by an insulating support 17 and a ball bearing 18 while maintaining high electrical insulation.

Power is supplied to the X-ray tube from an anode-side high-voltage power receiving device 19 and an anode-side high-voltage power receiving device 20 through ball bearings and sliding electrodes.

The X-ray tube rotates as its anode receives a magnetic field generated by a rotating magnetic field generating coil 21.

Inside the X-ray tube, the electron stream 22 emitted from the trance is deflected by a deflection coil 23 and impinges on the target at the same position as seen from the outside.

X-rays generated on the target are taken out from the radiation port 24.

Inside the X-ray tube storage container are 'SF6 and trifluoro-1.
, 1,2-trichloro-ethane (hereinafter chemical formula CCl2F
-CClF2) is enclosed.

The partial pressure of SF6 is about 2 atmospheres, and it is a gas at temperatures above 0° C., and maintains the insulation of the X-ray tube regardless of the level of the partial pressure of CCl2F-CClF2.

CCl2F -CC1F2G-jThe boiling point at 1 atm is 4
At 7.6°C and about 2 atmospheres, the boiling point rises further, so depending on the temperature, it becomes partly gas and partly liquid, maintaining equilibrium.

CCl2F-CClF2, which is a cooling medium 26 liquefied on the liquefier 25 and the wall of the X-ray tube container, is sprayed by a pump 27 through a pipe 28.
It is sent into the recess on the back of the anode, and while it touches the wall due to centrifugal force, it is vaporized by the heat of the anode.

Note that the liquefier 25, pump 27, spray pipe 28, etc. constitute a cooler of the present device.

Sealed rotary anode X-ray tubes are convenient to handle and have high short-term load characteristics, but they are difficult to cool for long-term loads because the anode rotates.

In order to improve this point, it is possible to integrate the anode and the X-ray tube envelope as in this embodiment, and rotate the anode together with the envelope to directly cool the back surface of the anode. In order to reduce the frictional resistance between the insulating refrigerant and the insulating refrigerant, insulation must be done with gas, and in the past, sufficient cooling could not be achieved.

However, in this embodiment, as mentioned above, since the insulating medium is a gas, it is possible to rotate the X-ray tube at high speed, and the heat of vaporization of the liquid is used for cooling, resulting in high efficiency. It is possible to obtain a rotating anode X-ray tube suitable for continuous use.

Furthermore, since the entire system is a single sealed system and the structure of the anode is simple, it is easy to handle and can be miniaturized.

In this example, by using a mixture of SF6 with a low boiling point and CCl2F/CC4F2 with a high boiling point as a medium for insulation and cooling, it is possible to prevent the gas pressure from decreasing too much at low temperatures and reducing the insulation ability. However, by controlling the temperature and pressure, only CC12F-CC4F2 can be used as the medium.

Furthermore, the chemical formula CCl3F, C5F, 2゜(CClF2)
2. A halogenated hydrocarbon having a boiling point of 0° C. or higher at 1 atmosphere, such as (CC12F)2, can also be used as the cooling medium.

In addition to SF6, nitrogen or the like can also be used as the low boiling point insulating gas.

FIG. 2 shows an example in which the present invention is applied to a fixed anode X-ray tube device of a neutral point grounding type.

FIG. 3 is an electrical circuit diagram of the embodiment of FIG. 2.

The X-ray tube is made by vacuum-tightly sealing an anode 12 and an anode 13 to an envelope 11.

A target 14 is provided on a part of the anode, and an electron gun 15 is provided on the tip of the anode.

The X-ray tube is held within the X-ray tube container 16 by an insulating support (not shown).

A part of the X-ray tube container serves as an X-ray emission port 24.

Power is supplied to the X-ray tube from an external power source 29 to an anode side transformer 30 and a positive tfJU lance 31. This is done via the foramen 1 to trans 32.

The anode side transformer and filament transformer are integrated.

During use, positive and negative high voltages are applied to the anode and anode every half wave of alternating current, but the tube current flows and is in operation only during the half period in which a negative high voltage is applied to the anode and a positive high voltage is applied to the anode. It is only the wave component.

The X-ray tube container is filled with a mixed medium of SF6 and CCl2F-CClF2, and the liquefied cooling medium 26CC12
F-CClF2 is vaporized at the anode, filling the X-ray tube container, cooled on the container wall, liquefied, and returned to the anode by the pump 27.

In this embodiment, the anode is installed facing upward as shown in the figure.

As is clear from the above explanation, in this embodiment, the entire wall of the tube vessel is used as a heat radiator, so it has extremely high cooling efficiency, and since the anode can be applied with a high voltage, the neutral point can be grounded. By using a transformer, it can be made into an open and compact device6.Furthermore, the structure of the X-ray tube container and the It does not impair its lightweight and portable properties in any way.

As described above, the gas-insulated X-ray tube device according to the present invention can greatly improve its cooling performance and can be used in a wider range of applications.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a longitudinal sectional view of another embodiment of the invention, and FIG. 3 is an electrical circuit diagram of the embodiment of FIG. 11...X-ray tube envelope, 12...Anode, 13...Anode, 16...X-ray tube container, 25... - Liquefier, 26...Liquified cooling medium, 27...Pump.

Claims (1)

[Scope of Claims] 1. A vacuum envelope whose interior is kept airtight, an anode disposed opposite to each other within the envelope, and an anode provided so that a portion thereof is exposed outside the envelope. , a tube storage container that airtightly stores the envelope, and a cooler that is connected to the container and circulates a refrigerant therein. A gas-insulated X-ray tube device characterized in that it is configured to be brought into contact with an exposed anode member. 2. The gas-insulated X-ray tube device according to claim 1, wherein the refrigerant is a halogenated hydrocarbon having a boiling point of O'C or higher.