X-ray source and the use thereof and method for producing X-rays

Abstract

An x-ray source in which monochromatic x-rays can be produced is provided. A method for producing X-rays and to the use of the x-ray source for x-raying bodies is also provided. A metallic film is arranged in a housing as a target which is bombarded with the electron beam. As a result, the metallic film is excited for emitting monochromatic x-rays, the relatively thin-walled target being modified such that the intended use for producing monochromatic x-rays is no longer possible. Therefore, advantageously, the production device can be pivoted for producing the electron beam as well as being able to wind the target on rollers.

Claims

1. An X-ray source having a housing in which a target is located that emits X-rays when being bombarded with an electron beam, wherein a metal foil is the target, and the electron beam is pivotable and the target is movable, such that the electron beam is capable of striking the target at a different location along a width of the target.

2. The X-ray source as claimed in claim 1, wherein the metal foil is made of at least one of a light metal and a plurality of light metals.

3. The X-ray source as claimed in claim 1, wherein the metal foil comprises at least one of a lanthanide, tungsten, molybdenum, and an alloy of at least two thereof.

4. The X-ray source as claimed in claim 1, wherein an anode is in a form of a tape, which is unwound from a first roller and wound onto a second roller.

5. The X-ray source as claimed in claim 4, wherein the first roller and the second roller are housed in vacuum locks of the housing.

6. The X-ray source as claimed in claim 4, wherein the second roller is mechanically coupled to a drive that is attached on an outside of the housing.

7. The X-ray source as claimed in claim 1, wherein a production device for the electron beam is of a pivotable design.

8. The X-ray source as claimed in claim 1, wherein the metal foil has a thickness of 0.1 μm to 0.5 μm.

9. A method for producing X-rays, in which a target in a housing of an X-ray source is bombarded with an electron beam and emits X-rays, wherein a metal foil is used as the target, and the electron beam is pivotable and the target is movable, such that the electron beam is capable of striking the target at a different location along a width of the target.

10. The method as claimed in claim 9, wherein monochromatic X-rays are produced using the target.

11. A method comprising: utilizing an X-ray source emitting monochromatic X-rays as claimed in claim 1 for X-raying a body, which produces differentiable contrasts at a wavelength of the X-rays used.

12. The X-ray source as claimed in claim 1, wherein the metal foil is comprised of aluminum.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 schematically illustrates the production of monochromatic X-rays in a foil in a schematic section; and

(3) FIG. 2 shows an exemplary embodiment of the X-ray source in schematic section.

DETAILED DESCRIPTION

(4) In FIG. 1, a metal foil 12 (illustrated as a detail) is provided as the target 11. An electron beam 13 strikes, with electrons 14, an atom 15 of the target material (for example aluminum). Also illustrated is the K-shell 16 of the atom 15, wherein the electron beam causes excitation of one of the electrons 17 of the K-shell 16 up to a different shell. When these electrons jump back, monochromatic X-rays 18 are emitted.

(5) FIG. 2 shows the construction of the X-ray source according to embodiments of the invention. The X-ray source itself is housed in an evacuable housing 19 which has a window 22. The electron beam 13 enters the housing 19. Subsequently, the electron beam strikes the target 11, wherein said target absorbs hardly any energy of the electron beam owing to its low thickness. However, part of the energy is converted, owing to an excitation of the atoms 15 (see FIG. 1) in the already described manner, into monochromatic X-rays 18 which can then leave the housing through the window 22. In order to accelerate the electrons 14 in the electron beam 13 sufficiently, what is known as an E-gun (i.e. an electron gun) is provided. Said E-gun has a cathode 23 which emits electrons if an electrical field is present. Said electrons are bundled using a lens 24. The electrical field is established by switching the target as an anode. Said anode can be operated at a potential of 100 to 300 kV, wherein a collector 27 at a potential of 40 to 120 kV is additionally used downstream of the target. The collector electrostatically decelerates the electron beam 13 which has nearly completely passed the target 11 and extracts the kinetic energy therefrom. The low-energy electrons of the decelerated beam are absorbed by the collector and conducted away as current.

(6) Also provided in the housing are a first roller 28 and a second roller 29. The target, which is present in the form of a tape 30, is wound onto the first roller 28 and is driven in a manner which is not illustrated further using an actuator M2 (located outside the housing in a manner known per se on a drive shaft for rotating the roller 29). In the process, the target 11 is unwound from the roller 28 and wound onto the roller 29. To permit simple replacement of the rollers 28, 29, vacuum locks 31, which are indicated in dashed-dotted lines, are provided such that the remaining space of the housing need not be vented when the rollers 28, 29 are replaced. The rollers 28, 29 are removed through the indicated doors 32.

(7) The electron gun is likewise mounted pivotably via a shaft 33. It is driven using a motor M1. The shaft 33 is parallel to the plane of the drawing in mounts 34, such that by pivoting the electron gun, the electron beam 13 can be pivoted over the entire width of the tape 30. The effect of the driving of the rollers 28, 29 is that the electron beam can also change the site of impact on the target in the direction of the longitudinal extent of the tape 30.