X-ray tube assembly

Abstract

An x-ray tube assembly includes an x-ray tube with a vacuum envelope in which an emitter and an anode are arranged. The emitter is configured to be heated by an external coil emitter heating current supply. The emitter is configured as a flat emitter and an adaptation circuit is arranged between the flat emitter and the coil emitter heating current supply. A coil-emitter-based x-ray tube assembly may be replaced by a flat emitter-based x-ray tube assembly without constructional changes.

Claims

1. An x-ray tube assembly comprising: an x-ray tube comprising a vacuum envelope; an emitter arranged in the vacuum envelope, wherein the emitter is configured to be heated by an external coil emitter heating current supply, and wherein the emitter is configured as a flat emitter; an anode arranged in the vacuum envelope; and an adaptation circuit disposed between the flat emitter and the coil emitter heating current supply, wherein the adaptation circuit is configured as an active impedance transformer, wherein the external coil emitter heating current supply provides a rectified alternating current, and the adaptation circuit includes a low-pass filter and an impedance transformation unit with at least one DC-DC converter, and wherein the low-pass filter is connected to the external coil emitter heating current supply, and the impedance transformation unit is connected to the flat emitter.

2. The x-ray tube assembly of claim 1, wherein the adaptation circuit is configured as a passive impedance transformer.

3. The x-ray tube assembly of claim 2, wherein the coil emitter heating current supply provides an alternating current, and wherein the adaptation circuit includes at least one transformer, the at least one transformer being connected on a primary side to the coil emitter heating current supply and on a secondary side to the flat emitter.

4. The x-ray tube assembly of claim 1, wherein the coil emitter heating current supply provides an alternating current, and wherein the adaptation circuit includes a rectifier arrangement, a downstream low-pass filter and an impedance transformation unit with at least one DC-DC converter, wherein the rectifier arrangement is connected to the coil emitter heating current supply and the impedance transformation unit is connected to the flat emitter.

5. The x-ray tube assembly of claim 1, wherein the coil emitter heating current supply provides an alternating current and the adaptation circuit includes an impedance transformation unit with at least one DC-DC converter, wherein the at least one DC-DC converter is connected on an input side to the coil emitter heating current supply and is connected on an output side to the flat emitter.

6. The x-ray tube assembly of claim 1, wherein the coil emitter heating current supply provides an alternating current and the adaptation circuit includes a transformer, a rectifier arrangement and a downstream low-pass filter, wherein the transformer is connected on a primary side to the coil emitter heating current supply and on a secondary side to the rectifier arrangement and the low-pass filter is connected to the flat emitter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an adaptation circuit in accordance with one embodiment of an x-ray tube assembly.

(2) FIG. 2 shows an adaptation circuit in accordance with another embodiment of an x-ray tube assembly.

(3) FIG. 3 shows an adaptation circuit in accordance with yet another embodiment of an x-ray tube assembly.

(4) FIG. 4 shows an adaptation circuit in accordance with still another embodiment of an x-ray tube assembly.

(5) FIG. 5 shows an adaptation circuit in accordance with one embodiment of an x-ray tube assembly.

DETAILED DESCRIPTION

(6) The exemplary embodiment of an x-ray tube assembly 100 shown in FIG. 1 includes an adaptation circuit 11, which is disposed between an external coil emitter heating current supply 12 and a flat emitter 13.

(7) The coil emitter heating current supply 12 provides an alternating current i.sub.AC(t). The adaptation circuit 11 is configured as a passive impedance transformer and, in the exemplary embodiment shown, includes a transformer 14 with a primary winding 141 and a secondary winding 142. The transformer 14 is connected on the primary side to the coil emitter heating current supply 12 and on the secondary side to the flat emitter 13. Through this arrangement, the flat emitter 13 is supplied with alternating current.

(8) The embodiment of an x-ray tube assembly 200 shown in FIG. 2 includes an adaptation circuit 21, which is disposed between an external coil emitter heating current supply 22 and a flat emitter 23.

(9) The coil emitter heating current supply 22 provides an alternating current i.sub.AC(t). The adaptation circuit 21 is configured as an active impedance transformer and, in the exemplary embodiment shown, includes a rectifier arrangement 24, a downstream low-pass filter 25 and an impedance transformation unit 26 with at least one DC-DC converter. The rectifier arrangement is connected to the coil emitter heating current supply 22 and the impedance transformation unit 26 is connected to the flat emitter 23. Through this arrangement, the flat emitter 23 is supplied with direct current.

(10) FIG. 3 shows an embodiment of an x-ray tube assembly 300 including an adaptation circuit 31, which is disposed between an external coil emitter heating current supply 32 and a flat emitter 33.

(11) The coil emitter heating current supply 32 provides a rectified alternating current i.sub.AC+DC(t). The adaptation circuit 31 is configured as an active impedance transformer and, in the exemplary embodiment shown, includes a low-pass filter 35 and an impedance transformation unit 36 with at least one DC-DC converter. The low-pass filter 35 is connected to the coil emitter heating current supply 32 and the impedance transformation unit 36 is connected to the flat emitter 33. Through this arrangement, the flat emitter 33 is supplied with direct current.

(12) The embodiment of an x-ray tube assembly 400 shown in FIG. 4 includes an adaptation circuit 41, which is disposed between an external coil emitter heating current supply 42 and a flat emitter 43.

(13) The coil emitter heating current supply 42 provides a direct current i.sub.DC(t). The adaptation circuit 41 is configured as an active impedance transformer and, in the exemplary embodiment shown, includes an impedance transformation unit 46 with at least one DC-DC converter. The impedance transformation unit 46 is connected on the input side to the coil emitter heating current supply 42 and is connected on the output side to the flat emitter 43. Through this arrangement, the flat emitter 43 is supplied with direct current.

(14) The exemplary embodiment of an x-ray tube assembly 500 shown in FIG. 5 includes an adaptation circuit 51, which is disposed between an external coil emitter heating current supply 52 and a flat emitter 53.

(15) The coil emitter heating current supply 52 provides an alternating current i.sub.AC(t). The adaptation circuit 51 is designed as an active impedance transformer and, in the exemplary embodiment shown, includes a transformer 54 with a primary winding 541 and a secondary winding 542. Furthermore, the adaptation circuit 51 includes a rectifier arrangement 55 and a downstream low-pass filter 56. The transformer 54 is connected on the primary side to the coil emitter heating current supply 52 and on the secondary side to the rectifier arrangement 55. The low-pass filter 56 is connected to the flat emitter 53. Through this arrangement, the flat emitter 53 is supplied with direct current.

(16) With the embodiments described in FIGS. 1-5, either alternating current (FIG. 1) or direct current (FIGS. 2-5) is supplied as heating current to the flat emitters. Consequently, a magnetic field is always created in the area of the emission surface of the flat emitter. This magnetic field deflects the electrons and may thereby have a negative effect on the focusing quality that may be achieved.

(17) In the event of alternating current being supplied (FIG. 1), the electrons are deflected in each case during a period to a maximum in a positive and negative direction. Whereas, when direct current is supplied (FIGS. 2-5), only a static deflection of the electrons occurs, which however is easier to manage relative to supplying alternating current and, thus, delivers better focusing qualities.

(18) The exemplary embodiments may be realized for a plurality of x-ray tube assemblies and is thus suitable for a plurality of x-ray tube assembly systems.

(19) The described solution enables a coil-emitter-based x-ray tube assembly to be replaced by a flat emitter-based x-ray tube assembly without constructional changes.

(20) It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

(21) While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications may be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.