Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
  • G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions

Definitions

• the invention relates to a method for the non-destructive testing of components of inhomogeneous materials with regard to material and orientation-specific density distribution by means of monochromatic X-ray examination and detector imaging.
• the invention is therefore based on the object of providing a method for the non-destructive testing of components of inhomogeneous materials which is also able to register spatial positions of different layers. This object is achieved by the characterizing features of claim 1.
• the measure according to the invention enables the use of a focusing system to examine components of inhomogeneous materials in the third dimension.
• Arched crystal Monochromators or totally reflecting X-ray mirrors can be used for the focusing system, a measuring gap, for example a detector, being arranged in the secondary focal point. A movement of the test specimen relative to the focusing system then enables components of inhomogeneous materials to be examined in all three spatial directions.
• Fig. 6 shows the principle for examination on the back of inaccessible samples
• FIG. 3 shows the functioning of a curved crystal monochromator.
• the corners ABC of a triangle lie on a circle with the radius R. With the center M of the circle, there are three isosceles triangles AEM, BCM and CAM, which define the side angles ⁇ , ⁇ , to have.
• the scattering angle is a beam going from A to C and diffracted there to B.
• the point D lying in the middle between A and B defines the line CD as the bisector of the angle 2 ⁇ lying at C, because the angle ACD is equal to the angle DCB. All circles, whose center is D, have a tangent at any point C lying on the circle ABC, which uses as a mirror, reflecting a beam directed from A to C to B.
• quartz crystal monochromators it has values of ⁇ 15o, ie ⁇ is negative and the base AB lies above the center M.
• the circle on which the focal points A, B and the surface of the curved crystal lie is called the focusing circle.
• Fig. 4 shows schematically the operation of a fine structure scattering chamber with a monochromator.
• An X-ray film is placed in this cylindrical chamber.
• the radiation generated in the focal spot of the X-ray tube is focused in the monochromator on a focal line located at the rear of the cylinder. Both focal spots and the surface of the monochromator lie on the aforementioned focusing circle.
• a thin powder preparation is attached to the entry side of the scattering chamber as a test specimen.
• the one from this examinee ter the Braggwinkel Scattered radiation is effective for all values from focused on another point of the X-ray film.
• the locations where the two marginal rays penetrate the sample can be recognized as the base AB according to FIG. 3, the radiation focal point lying on the cylinder carine being a possible point C according to FIG.
• the invention is based on the idea of not placing the short-armed focal line of a monochromator in an X-ray source, but in the irradiated test subjects, so that additional information can be obtained by the X-ray reflection generated there.
• the monochromator according to FIG. 4 appears in FIG. 1 as a monochromator 4, which gets its radiation from the area 3.
• Another idea of the invention is that the monochrcmator 4, due to its curved shape, can detect a beam of rays generated by a point in the region 3 at once.
• this is of particular importance for fiber composite materials because these materials consist of microparacrystals that only produce diffuse reflections.
• FIG. 3 on the path from the monochromator 4 to the detector 5 there is no longer any subject in the room, but the irritation which indicates the position of the examined subject's location.
• the carbon fibers of layer 8 are now perpendicular to the drawing plane, while in layer 9 they are parallel to the drawing plane, ie, in contrast to the so-called 002 reflections of layers 8, they are not in a reflective position.
• the test specimen can now be driven through the examination point 3 and all points of the composite material can be examined in the detector 5. It is therefore possible to explore the local position of the layers and at the same time to have them registered electronically or using a scintillation counter. Consequently, two maxima with one of the layer thickness distances can be on a registration strip of the test specimen 7 corresponding distance. If the subject 7 according to FIG.
• the layer 9 would be in a reflective position and a maximum would appear on the registration strip.
• the mono chromator 4 In order to be able to really catch the reflex 002 of a carbon fiber in the detector, the mono chromator 4 must be brought into a reflective position with the detector 5. For this purpose, both are firmly attached to a common support, for example on a support, which can be rotated about the focusing point 3 by means of the fine drive 10.
• the method according to the invention works with transmission.
• the reflections emerge on the side facing away from the x-ray tube.
• Particularly good measurement results are obtained when the reflections generated in a composite material emerge vertically from the test subject.
• a minimum of the disturbing scattered radiation then arrives at the detector 5.
• the input gap at detector 5 is also adjustable, i.e. can be adjusted for optimal resolution and intensity.
• FIG. 5 shows an example in which six reflective layers can be seen, with a larger gap apparently existing between layers 3 and 4.
• FIG. 7 shows an example of the composite material already shown in FIG. 5. The deeper layers are disadvantaged because the primary beam and the reflected beam have to travel a longer way through the test body.
• Fig. 7 shows an example with Molydän radiation, where the eleventh layer is only weakly recognizable. It can be seen very clearly that five reflecting layers are identified at one time and six times after rotating through 90 °, provided that this rotation takes place about an axis parallel to the layer normal.
• the invention relates to a further device by means of which all the layers detected in the reflection method are registered with the same intensity.
• a screen plate 11 is attached parallel to the test specimen 7 in front of the reflections 12 and 13 emerging from the composite body in such a way that its edge 14, which is adjusted parallel to the fan beam, just barely passes the beam coming from the rear surface.
• the screen plate 11 is provided with an x-ray absorption coefficient twice as large as the test body for adaptation.
• the setting to “depth of cut”, on which layer the boundary beam 13 is to be generated, is carried out by the fine drive 15 attached to the screen plate 11.

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• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Analysing Materials By The Use Of Radiation (AREA)

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Citations (3)

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• 1984
  • 1984-11-17 DE DE19843442061 patent/DE3442061A1/de active Granted
• 1985
  • 1985-05-07 WO PCT/DE1985/000147 patent/WO1986003005A1/de not_active Application Discontinuation
  • 1985-05-07 JP JP60502189A patent/JPS62500802A/ja active Pending
  • 1985-05-07 EP EP19850902446 patent/EP0201507A1/fr not_active Ceased
  • 1985-05-07 GB GB08617437A patent/GB2181630B/en not_active Expired

Patent Citations (3)

Non-Patent Citations (4)

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