SU473237A1 - X-ray tube - Google Patents

Description

This invention relates to remitgenotechnology.

X-ray tubes, known as x-ray, and x-rays in solid angle 2zg: sr are known. The exit window of these tubes has the shape of a Hemisphere and is made of a material that is transparent to X-rays, in particular beryllium.

The X-ray tube with such an exit window is known, it is contained, and the anticathode is in the form of a plate, the active surface of which (mirror) is parallel to the base of the exit window. The cathode is an annular filament surrounding the anticathode below its mirror so as not to obscure the radiation that occurs at the focus of the tube.

The disadvantage of this tube is the structural complexity caused by the need to create reliable electrical insulation between the cathode and the anticathode. Since the working voltage of the tube can reach several tens of kilovolts, the cathode and anticathode must be separated from each other by a considerable distance, which significantly increases the dimensions of the tube.

A known pulsed X-ray tube containing a shell with an exit window, which is made in the form of a hemisphere from a material that is transparent to X-rays, dispersed inside the shell of a cathode in the form of a disk and an anticathode formed by a layer of metal with an atomic number deposited on the inner surface of the output window. The anticathode is located opposite the cathode.

This tube is simpler in construction than the first, but it does not allow (as well as the first) to receive a constant in intensity radiation in a solid angle of 2 liters. In the first tube, this is due to the fact that part of the X-ray radiation is absorbed by the anticatode material, while in the second, the energy of the electrons that fall into separate parts of the anticathode is different.

The purpose of the invention is to create an X-ray tube with a raviomeric intensity of the generated radiation in a solid angle of 2jT sr.

The goal is achieved due to the fact that in the X-ray tube, the containment envelope with the exit window, which is made in the form of a hemisphere of a material that is transparent to X-rays, the cathode is also made in the form of a hemisphere and is located concentrically relative to the exit window.

To control the intensity of X-rays of CKOio radiation concentrically with respect to the cathode, an adjusting grid, a nanometer shaped hemisphere, is established.

And FIG. 1 and 2 and X-ray tubes are shown according to the invention, options.

The pulse X-ray tube shown in FIG. 1 comprises a shell consisting of a metal part 1, a cathode insulator 2 and an exit window 3, which are vacuum-sealed to each other. The output window 3 is made in the form of a hemisphere nz beryllium. An anticathode 4 is created on the inner surface of the window, which is a metal layer with a large atomic number, in particular rhenium.

The anticathode 4 has reliable electrical contact with the metal part 1 of the sheath, which also serves as the output of the anticathode.

Through the insulator 2 along its axis there passes the cathode output 5 in the form of a hollow tube, which is also a boom, which can be sealed after the internal tube is pumped out. At pin 5, a heated oxide cathode 6 is installed in the form of a hemi-sphere, concentrically located relative to the output window 3.

A continuous tube x-ray tube is shown in FIG. 2

The tube contains a shell formed by a glass part 7, a metal-ceramic leg 8 and exit windows 9. The exit window 9 is made in the form of a beryllium hemisphere. A layer of rhenium is deposited on the inner surface of the window, which is an anticathode 10. The exit window 9c with an anticathode is vacuum-tightly connected to flange II, which is also the output of the anticathode.

The cathode 12 is made in the form of a hemisphere, concentrically located relative to the output wrap 9 and is installed on the cathode holder 13. To heat the cathode 12 there is a filament 14, which is placed inside the cathode. The filament 14 is connected by conductor 15 to terminal 16 and through the holder 13 to terminal 17 of the cermet leg 8.

To control the intensity of the radiation, the tube is provided with a grid 18 having hemispheres concentrically located relative to the cathode 12. The grid 18 is fixed on a metal holder 19 connected to the metal flange 20 of the metal-ceramic leg 8.

The x-ray tube shown in FIG. 2, works as follows.

When voltage is applied to the filament 14 and to the cathode 12, the latter emits a stream of electrons, which, under the action of a voltage applied to the anticathode 10, rushes to the anticathode 10. When electrons strike the anticathode 10, x-rays are generated through the exit window 9 in solid angle 2n erased.

The intensity of the radiation emitted by the tube is controlled by the control grid 18. If the negative polarity voltage is applied to it, the X-ray intensity is attenuated, and when the positive polarity is applied it increases.

Due to the fact that the cathode 12 and the output window 9, and hence the anticathode 10, are made in the form of hemispheres, which are arranged concentrically relative to each other, the energies of electrons falling on the anticathode 10 are the same. Therefore, the x-ray radiation generated by the tube is isotropic in the whole solid angle 2 ster.

This tube is simple in design. Concentric placement of the tube electrodes ensures reliable and long-term operation, since with such an arrangement of the electrodes the field inside the tube does not have any noticeable peaks, the probability of breakdown decreases.

Subject invention

An X-ray tube comprising a housing with a hemisphere-shaped exit window of a material that is transparent to X-rays, a cathode located inside the housing and an anode formed by a layer of metal ic with a large atomic number deposited on the inner surface of the exit window In order to increase the uniformity of the radiation intensity in the solid angle 2 Ster, the cathode is made in the form of a hemisphere and is located in a conspicuous manner relative to the exit window.