JPH058860U - Rotating anode X-ray tube - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an X-ray emission window structure which has little X-ray absorption in a rotating anode X-ray tube and can withstand a large X-ray tube input without damage. A metal shield plate having a through hole is arranged at a position distant from an inner surface of a beryllium plate in a portion of an X-ray radiation window of a metal vacuum envelope.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an X-ray emission window structure of a rotary anode X-ray tube including a metal vacuum envelope.

[0002]

[Prior Art]

 As described in Japanese Utility Model Laid-Open No. 53-134675, a conventional rotary anode X-ray tube has an inner shielding plate made of graphite as an X-ray emission window provided at a predetermined position of a metal vacuum envelope. In addition, by arranging a beryllium plate hermetically sealed on the outside, damage to the beryllium plate due to scattered electrons and secondary electrons from the target plate or the cathode, and radiant heat is prevented.

[0003]

[Problems to be solved by the device]

 The above-mentioned conventional technique has an inevitable effect of X-ray absorption due to the graphite shielding plate, and has a problem for the purpose of reducing X-ray absorption. An object of the present invention is to provide an X-ray radiation window structure which has a small X-ray absorption and can withstand a large X-ray tube input without damage.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a rotating anode X-ray tube having a metal vacuum envelope provided with an X-ray radiation window having a beryllium plate, and a through hole formed at a position distant from the inner surface of the beryllium plate. The metal shielding plate provided with is arranged.

[0005]

[Action]

 The cause of damaging the X-ray radiation window is scattered electrons, secondary electrons and radiant heat generated when the X-ray tube is operated. Since the focus position of the anode serving as the X-ray generation source is deviated to the X-ray emission window side with respect to the envelope, the influence of scattered electrons and secondary electrons is larger than that of radiation heat. For this reason, if a metal shielding plate with a through hole is used, the metal shielding plate absorbs scattered electrons and secondary electrons, so that the influence on the X-ray emission window made of beryllium can be reduced. Since the X-ray absorption is not hindered by the through hole, it is possible to obtain a rotating anode X-ray tube which has a small X-ray absorption and can withstand a large X-ray input.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a vertical sectional view of a rotary anode X-ray tube according to an embodiment of the present invention. A cathode 3 and a rotating anode 4 are arranged on both sides of a metallic vacuum envelope 1 via vacuum envelopes 2 and 2a made of an insulating material such as glass or ceramics. An X-ray radiation window 5 is hermetically connected to a predetermined position of the metal vacuum envelope 1. The X-ray radiation window 5 is airtight to the metal shielding plate 7 provided with the through hole 6 and the metal shielding plate 7 so that the through hole 6 is located inside from the portion where the through hole 6 is provided. Beryllium plate 8 connected. The metal shield plate 7 is made of a metal having a good thermal conductivity such as copper, or a metal having a good heat resistance such as stainless steel or molybdenum, and the size of the through hole 6 is a required X-ray irradiation field. And the size required to obtain.

During operation of the X-ray tube, the heat generated in the rotating anode 4 is radiated almost evenly to the entire metal vacuum envelope 1 including the X-ray emission window 5, but scattered electrons or secondary electrons are not generated. Most of it is intensively flown into the X-ray radiation window 5 and the surrounding metal vacuum envelope portion to be converted into heat. In that case, the beryllium plate 8 is separated from the portion of the through hole 6 of the metallic shielding plate 7, so that scattered electrons or secondary electrons hardly flow in and the temperature rise is small. Further, the heat generated by the metal shield plate 7 is radiated to the outside of the X-ray tube by heat conduction. On the other hand, the X-rays generated at the focal point of the rotating anode 4 are radiated to the outside from the beryllium plate 8 through the through holes 6, and the beryllium plate 8 is not damaged even if it is made thin because the temperature rise is small. Since it does not exist, X-ray absorption in the X-ray radiation window portion can be extremely reduced. The size of the beryllium plate 8 does not increase as much as the temperature of the beryllium plate 8 as described above, so that a shape and size convenient for working can be selected.

FIG. 2 is a longitudinal sectional view of a main part showing another embodiment of the X-ray radiation window. In this embodiment, a through hole 6 is provided in the installation portion of the X-ray radiation window 5 of the vacuum envelope 1 made of metal, and a beryllium plate 8 is attached to a window frame 9 airtightly connected to the outside of the vacuum envelope 1 made of metal. , Is attached airtightly from the through hole 6. Also in this embodiment, the same effect as in the case of FIG. 1 is obtained.

[0009]

[Effect of the device]

 According to the present invention, even if a large X-ray tube input is applied, the X-ray emission window is not damaged, and the X-ray absorption in the X-ray emission window can be reduced, so that a large X-ray output can be easily performed. The effect that can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a rotary anode X-ray tube according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing another embodiment of the X-ray radiation window part.

[Explanation of symbols]

 1 Metal Vacuum Enclosure 5 X-Ray Radiation Window 6 Through Hole 7 Metal Shielding Plate 8 Beryllium Plate 9 Window Frame

Claims (1)

[Claims for utility model registration] 1. A rotating anode X-ray tube having a metal vacuum envelope provided with an X-ray radiation window equipped with a beryllium plate, at a position distant from the inner surface of the beryllium plate. A rotating anode X-ray tube having a metal shielding plate provided with a through hole.