Detector array and device for absorption imaging comprising the detector array

Abstract

This invention relates to a detector array (1) for detecting electromagnetic radiation, the detector array (1) comprising a plurality of detector elements (2) arranged sequentially along a scan line extending in a first direction (Y), each of the plurality of detector elements (2) having a detector surface (3) for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal, wherein the surface normals (4, N) of each of the detector surfaces (3) extend in a common plane (S) and converge to a common focal point (5), wherein the common plane (S) extends in the first direction (Y), and for at least two detector elements (2), the distances between the common focal point (5) and the detector surface (3) along the respective surface normals (4, N) are different. Furthermore, this invention relates to a radiographic examination system (20) including the detector array (1).

Description

Technical Field

[0001] This invention relates to a detector array for detecting electromagnetic radiation, the detector array comprising a plurality of detector elements arranged sequentially along a scan line extending in a first direction, each of the plurality of detector elements having a detector surface for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal, wherein the surface normals of the respective detector surfaces extend in a common plane and converge to a common focal point. Furthermore, this invention relates to a radiographic examination system including the detector array. Background Technology

[0002] Detector arrays for radiographic examination may include detectors having multiple detector elements arranged in a two-dimensional configuration, such as an m×n matrix, as disclosed in US 2002 / 0110216 A1. Alternatively, multiple detector arrays having scan lines extending in a first direction may be arranged in a direction perpendicular to the first direction to produce a two-dimensional configuration, as disclosed in EP 1 010 021 B1. Detector elements include a detection surface for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal. The detection surface may include a scintillator suitable for converting the electromagnetic radiation into radiation detectable by a photodiode. Photodiodes may be arranged on each detector element.

[0003] A radiographic inspection system may include a detector array, a radiation source, and a transmission device. The radiation source generates a radiation beam comprising a single beam of rays that spans a radiation plane. The transmission device transports the object to be inspected along a transmission path transverse to the radiation plane, the transmission path being positioned between the radiation source and the detector array. The radiation source may be an X-ray source.

[0004] For example, in a known setup of a radiographic inspection system, as described in EP 3 078 944 A1, the article to be inspected is transported on a conveyor belt along a transport path positioned between a radiation source and a detector array. Typically, the electromagnetic radiation from the radiation source is emitted as a fan-shaped planar beam. The detector has an array of detector elements arranged in a linear form along scan lines extending in a first direction. The radiation plane formed by the fan-shaped radiation beam and the detector array lie in a plane extending substantially perpendicular to the transport path of the article. As the article moves across this plane, the detector's update frequency is coordinated with the speed of the conveyor belt, such that the signal sequence generated by the detector array can be converted into a grating dot pattern with different brightness values, representing a shadow image of the article positioned between the radiation source and the radiation detector. The shadow image corresponds to a transmission image of the article, i.e., the shadow image corresponds to X-rays absorbed by and transmitted through the article. Absorption is then determined from the transmission image. This generates a two-dimensional image of the article to be inspected. If the scanned item contains foreign objects, such as metal fragments, that have a lower transmittance to the radiation source than the scanned item, the radiographic image will show such foreign objects as darker areas within the transparent shadow image of the scanned item.

[0005] Radiographic examination has many applications, including but not limited to the food and beverage industry and forensic medicine. In the food and beverage industry, radiographic examination is used to detect foreign objects in articles. For example, the aforementioned radiographic examination system can be used to detect foreign objects in food, such as meat.

[0006] In many applications, X-ray absorption imaging is used to image objects containing materials of varying thicknesses. In such cases, it is advantageous to record multiple images of the same object at different X-ray energies, rather than just a single X-ray absorption image. From these images, different materials can be distinguished based on their energy-dependent X-ray absorption.

[0007] The most common method for recording multiple images of the same object at different X-ray energies is dual-energy X-ray imaging. In this method, the same object is exposed to varying X-ray energies, or a detector capable of resolving two or more different energies is used.

[0008] There are various technological implementations of detectors capable of distinguishing two or more different energies. Typically, such detectors consist of multiple detector elements capable of recording X-ray signals independently of each other. Modern semiconductor detectors can measure the energy of a single X-ray photon (photon counting), and therefore can distinguish the X-ray photon energy in each detector element.

[0009] Another feasible approach for dual-energy X-ray detectors is to use a scintillator to convert X-ray photons into visible light and a photodiode to detect the emitted light. Typically, detector elements comprising a first detector component and a second detector component with different scintillator materials and thicknesses are used to form a dual-energy X-ray detector.

[0010] The first and second detector components of each detector element can be placed side by side. Alternatively, the first and second detector components can be stacked, as disclosed in US 4,511,799. For stacked dual-energy X-ray detectors, the first (“upper”) detector component facing the X-ray source typically records low-energy images. Below the upper detector component, a filter, such as a thin metal plate, can be arranged to prevent low-energy X-rays from reaching the second (“lower”) detector component arranged below and adapted to record high-energy images.

[0011] As explained above, and with reference to the schematic cross-sectional view of the radiographic examination system, Figure 5 To further explain, a radiographic inspection system for imaging moving objects may include a detector array 100 and a radiation source 120. The detector array 100 includes a plurality of detector elements 101 arranged sequentially along a scan line extending in a first direction Y. The radiation source 120 emits a radiation beam including a ray 132 that forms a radiation plane. The detector elements 101 include a detection surface for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal. The detection surface is arranged perpendicular to the radiation plane. The detector array 100 may be arranged symmetrically with respect to the focal point 131 of the radiation beam 130. Therefore, radiation incident on the detection surface of the detector array 100 may have an incident angle α of approximately 90° at the center C of the detector array 100. However, towards the outer ends of the detector array 100, the incident angle α is different from 90°.

[0012] In the following case: the detector array 100 includes stacked dual-energy X-ray detector elements 101, each detector element including an upper detector component 102 and a lower detector component 103, wherein each of the detector components 102 and 103 has a detection surface, such as Figure 5As shown, the fact that the incident angle α on the detection surfaces of the upper detector component 102 and the lower detector component 103 is different from 90° may have the following consequences: At the edge 101a of the planar detector array 100, a ray 132 incident on the detector array 100 may be incident on the upper detector component 102 of a detector element 101, but the ray 132 will not be incident on the lower detector component 103 of the same detector element 101. Instead, the ray 132 will be incident on the lower detector component 103 of the adjacent detector element 101. This reduces the resolution of the detector array 100.

[0013] To improve this situation, it is known in the art to arrange the detector elements 101 of the detector array 100 continuously on an arc (see...). Figure 6 Each detector element 101 has a detection surface 104 for receiving electromagnetic radiation, and the surface normals 105 of each of the detection surfaces 104 extend in a common plane and converge to a common focal point 107. When the detector array 100 and the radiation source 120 are arranged relative to each other such that the common plane coincides with the radiation plane formed by the rays 132 of the radiation beam 130 emitted from the radiation source 120 and the common focal point 107 coincides with the focal point 131 of the radiation beam 130, each detector element 101 is irradiated at a 90° angle by the radiation beam 130 at its center of mass 106.

[0014] Current advancements in X-ray imaging technology have led to a reduction in pixel size in X-ray detectors. This development is driven by the need for better image quality, such as detecting smaller contaminants in food inspection. This advancement has introduced additional challenges to the construction of X-ray detectors. While the curved arrangement of the individual detector elements described above means that electromagnetic radiation is incident on the upper and lower detector members at approximately a 90° angle at the centroid of each detector surface, this is no longer the case for the edges of individual detector elements. Here, an incident angle deviates from 90°. Therefore, as in the case of planar detector arrays, rays incident on the upper detector member of a detector element may not be incident on the lower detector member of the same element. This effect may be related to the 0.4 mm size of detector elements currently available. Consequently, the resolution gain of small detector elements may be compromised.

[0015] Another challenge of detector arrays known in the art is the precise alignment of detector elements along a first direction. When all detector elements are aligned on an arc, the gap between two adjacent detector elements should be as small as possible, since radiation cannot be detected in the gap. This requires careful alignment of the detector elements and carries the risk of damaging the edges of the detector elements during installation. Otherwise, relatively large gaps may exist between adjacent detector elements, which can reduce the resolution of the detector array. Summary of the Invention

[0016] In view of the problems existing in the prior art, the purpose of the present invention is to further develop the detector array and X-ray inspection system mentioned above, so as to achieve high detection accuracy and simple manufacturing.

[0017] According to a first aspect of the invention, this objective is achieved by further developing a detector array as mentioned above, in which a common plane extends along the first direction, and for at least two detector elements, the distances along the normal direction between the common focal point and the detection surface are different for each other.

[0018] According to a first aspect of the invention, a detector array for detecting electromagnetic radiation is provided, the detector array comprising a plurality of detector elements. The plurality of detector elements may include two, three, or more detector elements. The detector elements are arranged continuously along a scan line extending in a first direction. This arrangement realizes a "one-dimensional" detector array. During use of the detector array, an object to be inspected moves along a transmission path transverse to, or for example, perpendicular to, the scan line to create a two-dimensional image. The plurality of detector arrays according to the invention can be arranged along a direction transverse to, or for example, perpendicular to, the scan line.

[0019] Each of the plurality of detector elements has a detector surface for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detector signal. The detector signal may be an electrical signal. Each detector surface includes a plurality of surface normals. For each detector surface, there exists at least one surface normal such that the surface normal extends in a common plane, and the common plane extends in the first direction. That is, all these surface normals lie within the common plane. The direction along the surface normal is denoted as the normal direction. Furthermore, the surface normals converge to a common focus. The common focus may be a point or a region. For example, when the detector elements are arranged on an arc with a center point M, as is known in the prior art (see...). Figure 6 The common focus corresponds to the center M, and the surface normal is perpendicular to the centroid of the detection surface of each detector element.

[0020] According to a first aspect of the invention, for at least two detector elements, the distance along the normal direction between the common focus and the detection surface is different. That is, if the distance along the surface normal of the detector element converging to the common focus between the detection surface of one of the two detector elements is defined as d1, and the distance along the surface normal of the detector element converging to the common focus between the detection surface of the other of the two detector elements is defined as d2, then d1 is different from d2. In other words, at least two detector elements are offset from each other in a common plane. This differs from an arrangement where all detector elements are arranged on an arc. When arranged on an arc, the distance along the normal direction between the common focus and the detection surface is the same for all detector elements.

[0021] The offset of at least two of the plurality of detector elements simplifies the alignment between adjacent detector plates, allows for easy installation of a large number of small detector elements, and reduces the volume of the detector array by lowering its height. The height of the detector array can be defined as the maximum extension of the detector array in the common plane.

[0022] In one embodiment of the detector array according to the invention, the facing end faces of at least two adjacent detector elements can be aligned along a straight line passing through a common focus. The facing end faces each other in a first direction. In this embodiment, there is no region between two adjacent detector elements where radiation from a radiation source located at the common focus of the detector array, such as a fan-shaped radiation beam, cannot be detected by the detector array. That is, there is no undetectable gap between adjacent detector elements in the first direction. This improves the detection efficiency of the detector array. In one possible example, the facing end faces of each pair of adjacent detector elements can be aligned along a straight line passing through the common focus. In this way, the detection efficiency can be further improved.

[0023] According to another embodiment of the detector array of the present invention, for each of the plurality of detector elements, there may be at least one adjacent detector element such that the distance between the common focal point and the detection surface along the normal direction is different for two adjacent detector elements. This arrangement allows for minimizing the extension of the detector array in the normal direction. That is, the height of the detector array can be reduced.

[0024] In another embodiment of the detector array according to the invention, for each of the detector surfaces, the surface normals at the centroid of the respective detector surface converge to the common focus. In this way, the angle of incidence of radiation at the centroid of each detector surface along the first direction is 90°. However, the invention is not limited to this configuration. For example, for each of the detector surfaces, surface normals may exist at the ends of the detector surfaces along the first direction, and these surface normals converge to the common focus. When the radiation source is arranged at the common focus of the detector array, the angle of incidence of radiation at the ends of each detector surface along the first direction is 90°.

[0025] Furthermore, the centroid of the detection surface can be aligned along a straight line. This straight line can extend in a first direction. In this way, the height of the detector array can be limited by the size of the detection surface. Therefore, the height of the detector array can be further reduced.

[0026] In one embodiment of the detector array according to the invention, a more constant magnification factor in the resulting image can be achieved by the following setting: for at least one pair of detector elements, for two points A and B located at the intersection of the surface normal at the centroid of the detection surface of the respective detector element in the pair and the inspection plane used to arrange the item to be inspected, there exists a constant distance ratio a / a′ = b / b′ between the distances a and b between points A and B and the common focal point, and between the distances a′ and b′ between points A and B and the respective detection surfaces. When using the detector array, the item to be inspected is arranged in the detection plane. Then, for at least one pair of first and second detector elements, point A at the intersection of the surface normal at the centroid of the detection surface of the first detector element and the detection plane can be identified. Furthermore, point B at the intersection of the surface normal at the centroid of the detection surface of the second detector element and the detection plane can be identified. Then, the distance between the common focal point and point A is represented by a, and the distance between point B and the common focal point is represented by b. Furthermore, the distance between point A and its projection on the first detector element is represented by a′, and the distance between point B and its projection on the second detector element is represented by b′. Since the detector elements are arranged in a detector array such that the distance ratio a / a′ = b / b′ is the same for at least two detector elements, a more constant magnification factor can be guaranteed. That is, a region of size s near point A and a region of size s near point B are magnified to approximately the same size image at the detector array. In this way, the problem that the magnification factor is not constant across the entire detector array in the prior art is overcome. Preferably, the distance ratio a / a′ = b / b′ is the same for each pair of detector elements in the detector array.

[0027] The detection surface of the detector element can have a variety of possible geometries. For example, at least one of the detection surfaces may include a flat surface. Such a detection surface is particularly easy to manufacture. Additionally or alternatively, the detection surface may have a rectangular outer perimeter. In this case, the centroid corresponds to the center of the rectangle. This is advantageous for continuously arranging the detector elements along a first direction.

[0028] The detector array described above can be used to detect electromagnetic radiation of any wavelength. In one possible embodiment of the detector array according to the invention, the detector elements can be adapted to detect X-ray radiation. In this case, the detector according to the invention can be used, for example, for X-ray absorption imaging.

[0029] In one embodiment of the invention, the detector element may include a stacked dual-energy X-ray detector element. The stacked dual-energy X-ray detector element includes a first detector component and a second detector component stacked one on top of the other. The first detector component and the second detector component each include a first detection surface and a second detection surface. The first and second detection surfaces are operable to convert received electromagnetic radiation into a corresponding detection signal. The first and second detection surfaces include surface normals, wherein for each surface normal on the first detection surface, there may be a surface normal on the second detection surface such that the two surface normals are aligned along a straight line. The first and second detection surfaces may include flat surfaces arranged parallel to each other. During use of the detector array, the first (“upper”) detector component facing the radiation source is adapted to detect a first radiation energy E1. The second (“lower”) detector component, arranged below the upper detector component, is adapted to detect electromagnetic radiation having a second energy E2. The first and second detector components are adapted such that the energy detected by the upper detector component is lower than the energy detected by the lower detector component, i.e., E1 < E2. A filter, such as a thin metal plate, may be arranged between the upper and lower detector components to prevent low-energy radiation from reaching the lower detector component.

[0030] In one embodiment of the detector array according to the invention, each of the plurality of detector elements may include a scintillator. The scintillator may be adapted to convert electromagnetic radiation into radiation detectable by a photodiode. Each detector element may include a photodiode adapted to detect radiation emitted from the scintillator.

[0031] In another example of the detector array according to the invention, the detector array may further include a support on which each detector element can be detachably mounted. This allows for very easy replacement of damaged detector elements. For example, each detector element may include a protrusion, and the support may include a plurality of recesses adapted to receive the protrusion, such that the detector element can be stably mounted on the support.

[0032] According to a second aspect of the invention, a radiographic inspection system is provided, the system comprising: a radiation source for generating a radiation beam, the radiation beam including a beam of rays forming a radiation plane, the radiation beam including a focal point; a detector array according to the invention; and a transmission device for transmitting an item to be inspected along a transmission path transverse to the radiation plane, the transmission path being disposed between the radiation source and the detector array, wherein the detector array is arranged such that the common plane coincides with the radiation plane and the common focal point coincides with the focal point.

[0033] According to one embodiment of the present invention, the transmission device may include a conveyor belt. The transmission path may be perpendicular to the radiation plane.

[0034] According to another aspect of the invention, the radiation source may include an X-ray source. The radiographic examination system may be a system for absorption imaging, particularly for X-ray absorption imaging. The radiation source may emit a fan-shaped radiation beam, the rays of which form a radiation plane. Attached Figure Description

[0035] In the following description, the invention will be illustrated in more detail by way of example with reference to the accompanying drawings. In the drawings:

[0036] Figure 1 This is a side view of a detector array according to the present invention, wherein the common focus of the detector array is arranged at the focus of the radiation source;

[0037] Figure 2 Is with Figure 1 The similar view shown illustrates the geometric relationship of the detector array;

[0038] Figure 3 yes Figure 2 A magnified view of region D in the image;

[0039] Figure 4 This is a perspective view of the radiographic examination system according to the present invention;

[0040] Figure 5 It is a side view of the detector array and radiation source based on existing technology;

[0041] Figure 6 It is a three-dimensional diagram of a radiographic examination system based on existing technology. Detailed Implementation

[0042] Figure 1 This is a side view of the detector array 1 according to the present invention. The detector array 1 includes a plurality of detector elements 2 arranged continuously along a scan line extending in a first direction Y.

[0043] Figure 1A radiation source 30 emitting electromagnetic radiation, comprising a beam of rays, is also shown. Figure 1 In this embodiment, the radiation beam is in the form of a fan-shaped radiation beam 31, but the invention is not limited thereto. The rays of the radiation beam form a radiation plane RP. Figure 1 In the middle, the radiation plane RP coincides with the paper plane.

[0044] Items to be inspected can be transported across the radiating plane RP. For this purpose, a conveyor belt can be used. The conveyor belt can transport items transversely to, and particularly perpendicularly to, the inspection plane 8 of the radiating plane RP.

[0045] Each of the detector elements 2 has a detection surface 3 for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal. Surface normals 4 of each detection surface 3 extend in a common plane S, which extends in the first direction Y. The surface normals 4 converge to a common focal point 5. That is, all surface normals 4 lie within the common plane S. Each surface normal 4 defines a normal direction N. Unlike the arcuate arrangement of detector elements known in the art, for each detector element 2 there are adjacent detector elements 2 such that for two adjacent detector elements 2, the distance along the normal direction N between the common focal point 5 and the detection surface 3 is different. That is, if the distance along the surface normal N converging to the common focal point 5 between the detection surface 3 of one of the two detector elements 2 is defined as d1, and the distance along the surface normal N converging to the common focal point 5 between the detection surface 3 of the other of the two adjacent detector elements 2 is defined as d2, then d1 is different from d2. Figure 1 It can be immediately and clearly seen that the height of detector array 1, that is, the extension of detector array 1 in the common plane S, is affected by... Figure 1 The length I of the detection surface 3 shown is limited. This allows for a very compact arrangement of the detector elements, and thus a very compact detector array 1. Furthermore, the detector array 1 allows for easy installation and / or replacement of individual detector elements 2.

[0046] In addition, such as in Figure 3 The best view is in the middle. Figure 3 yes Figure 1 and 2The enlarged view of region D in the illustrated embodiment shows that the facing end faces 6 of adjacent detector elements 2 are aligned along a straight line L passing through the common focal point 5. In this way, there is no gap between adjacent detector elements 2 in the first direction Y that would prevent the detection of the fan-shaped radiation beam 31. This improves the detection efficiency of the detector array 1 compared to an arrangement where gaps exist between adjacent detector elements, preventing radiation from being received from either of the two adjacent detector elements 2.

[0047] In addition, Figure 1 In the illustrated embodiment, for each of the probe surfaces 3, a surface normal 4 exists at the centroid 7 of the respective probe surface 3, and the surface normal 4 converges to a common focal point 5 (see [link to documentation]). Figure 3 (Enlarged view). The probe surface 3 can have a rectangular outer perimeter and can be flat. In this case, the centroid 7 corresponds to the center of the flat rectangular probe surface. That is, in Figure 1 When the focal point 32 of the radiation source 30 coincides with the common focal point 5 of the detector array 1, the radiation emitted from the fan-shaped radiation beam 31 is incident at a 90° angle on the detection surface 3 of the detector element 2 at the centroid 7 of the detection surface 3 (see...). Figure 3 ).

[0048] Figure 1 Each detector element 2 in the illustrated embodiment may include a stacked dual-energy X-ray detector element. This will be referred to below. Figure 3 To explain in more detail.

[0049] As described above, the detector element 2 may include a detector surface 3 having a flat surface. Furthermore, the detector surface 3 may have a rectangular outer perimeter. In this way, arranging the detector element 2 in the detector array 1 can be particularly easy.

[0050] In absorption imaging, a region of size *s* of the object to be inspected is represented as an image on a detector array, where the size of the image of this region, *s′*, is larger than the size *s* of the object's region. This effect is called magnification, and *s′* / *s* is called the magnification factor. A problem with existing detector arrays is the non-constant magnification factor. That is, two regions of the same size of the object to be inspected are represented as images of different sizes at the detector. The detector array of the present invention overcomes this problem. For this purpose, refer to... Figure 2 , Figure 2 Is with Figure 1The view shown is similar to the one depicting the geometry of detector array 1. A and B represent two points located at the intersections of the surface normal 4 and the inspection plane 8 at the centroids 7 of the detection surfaces 3 of the first and second detector elements 2, respectively. The distance between the common focus 5 and point A is denoted as a, the distance between the common focus 5 and point B as b, the distance between point A and the first detector element of detector array 1 along the surface normal 4 as a′, and the distance between point B and the second detector element of detector array 1 along the surface normal 4 as b′. Since all the centroids 7 of detector elements 2 are arranged on a single straight line G, the distance a / a′ = b / b′ is constant according to the intercept theorem. This relationship guarantees a more constant magnification factor. That is, in the inspection plane 8, the regions of size s of items near point A and near point B on the conveyor belt will be magnified to (approximately) the same size at the corresponding detector elements 2 of detector array 1. Preferably, the distance ratio defined above is the same for each pair of detector elements 2.

[0051] Figure 3 yes Figure 2 An enlarged view of region D in the image. Figure 2 A detector element 2 comprising stacked dual-energy X-ray detector elements is shown. Each detector element 2 includes a first detector component 2a and a second detector component 2b stacked one on top of the other. The first detector component 2a faces the radiation source 30. The first detector component 2a is adapted to detect radiation with energy E1, and the second detector component 2b is adapted to detect radiation with energy E2, wherein E2 is greater than E1. That is, the first detector component 2a can be considered a low-energy detector, and the second detector component 2b can be considered a high-energy detector. Since the first detector component 2a and the second detector component 2b are stacked one on top of the other, the rays 33 of the radiation beam 31 are incident at a 90° angle at the centroid 7 of the detection surfaces 3 of the first detector component 2a and the second detector component 2b. A distance can exist between the first detector component 2a and the second detector component 2b. Therefore, the detector array according to the invention avoids the problem of the prior art, namely, that rays incident on the upper detector component of the detector element are not incident on the lower detector component of the same detector element but on the adjacent detector element. In this way, the resolution of the detector array 1 is improved compared to the prior art arrangement in which the detection surfaces are arranged in a straight line.

[0052] Figure 4This is a perspective view of a radiographic inspection system 20 according to the present invention. The radiographic inspection system 20 includes a radiation source 30. The radiation source 30 may be an X-ray source. The radiation source generates a fan-shaped radiation beam 31, wherein the rays of the radiation beam form a radiation plane RP. The fan-shaped radiation beam 31 includes a focal point 32.

[0053] The radiographic examination system 20 also includes a detector array 1 according to the present invention. The detector array 1 may be... Figure 1 and Figure 2 The detector array 1 shown.

[0054] Furthermore, the radiographic inspection system 20 includes a transport device 40 for transporting the article 50 to be inspected along a transport direction T, particularly perpendicular to the radiation plane RP. The transport device 40 includes a conveyor belt 41 for transporting the article 50 along the transport direction T. The article is transported in the inspection plane 8. The transport path T is positioned between the radiation source 30 and the detector array 1. The detector array 1 is arranged such that its common plane S coincides with the radiation plane RP. Furthermore, the common focal point 5 of the detector array 1 coincides with the focal point 32 of the radiation source 30. Figure 4 The radiographic inspection system 20 shown is very compact because the detector array 1 is also very compact. Furthermore, the detector array 1 according to the invention allows for high-precision imaging of the item 50 to be inspected. The radiographic inspection system 20 can be used for X-ray absorption imaging.

Claims

1. A detector array (1) for detecting electromagnetic radiation, the detector array (1) comprising a plurality of detector elements (2) arranged continuously along a scan line extending in a first direction (Y), each of the plurality of detector elements (2) having a detector surface (3) for receiving electromagnetic radiation and operable to convert the received electromagnetic radiation into a corresponding detection signal, wherein, The surface normals (4) of each of the detector surfaces (3) extend in a common plane (S) and converge to a common focus (5), wherein the common plane (S) extends along the first direction (Y), and for at least two detector elements (2), the distance between the common focus (5) and the detector surface (3) along the normal direction (N) that is the direction along the surface normal (4) is different, characterized in that the facing end faces (6) of each pair of adjacent detector elements (2) are aligned along a straight line (L) passing through the common focus (5), and all the centroids (7) of the detector surfaces (3) are aligned along a straight line (G).

2. The detector array (1) according to claim 1, wherein, For each of the plurality of detector elements (2), there exists at least one adjacent detector element (2) such that for two adjacent detector elements (2), the distance between the common focus (5) and the detection surface (3) along the corresponding surface normal direction (N) is different.

3. The detector array (1) according to any one of the preceding claims, wherein, For each of the probe surfaces (3), there is a surface normal (4) at the centroid (7) of the corresponding probe surface (3) that converges to the common focal point (5).

4. The detector array (1) according to claim 1 or 2, wherein, A more constant magnification factor in the resulting image is achieved by the following settings: For at least one pair of detector elements (2) among the plurality of detector elements (2), for two points A and B at the intersection of the surface normal (4) at the centroid (7) of the detection surface (3) of the corresponding detector element (2) of the pair of detector elements (2) and the inspection plane (8) used to arrange the item to be inspected, there exists a constant distance ratio a / a' = b / b' between the distances a and b between points A and B and the common focal point (5) and the distances a' and b' between points A and B and the corresponding detection surface (3).

5. The detector array (1) according to claim 3, wherein, A more constant magnification factor in the resulting image is achieved by the following settings: For at least one pair of detector elements (2) among the plurality of detector elements (2), for two points A and B at the intersection of the surface normal (4) at the centroid (7) of the detection surface (3) of the corresponding detector element (2) of the pair of detector elements (2) and the inspection plane (8) used to arrange the item to be inspected, there exists a constant distance ratio a / a' = b / b' between the distances a and b between points A and B and the common focal point (5) and the distances a' and b' between points A and B and the corresponding detection surface (3).

6. The detector array (1) according to any one of claims 1-2 and 5, wherein, At least one of the probe surfaces (3) includes a flat surface.

7. The detector array (1) according to claim 3, wherein, At least one of the probe surfaces (3) includes a flat surface.

8. The detector array (1) according to claim 4, wherein, At least one of the probe surfaces (3) includes a flat surface.

9. The detector array (1) according to any one of claims 1-2, 5, 7-8, wherein, At least one of the probe surfaces (3) has a rectangular outer perimeter.

10. The detector array (1) according to claim 3, wherein, At least one of the probe surfaces (3) has a rectangular outer perimeter.

11. The detector array (1) according to claim 4, wherein, At least one of the probe surfaces (3) has a rectangular outer perimeter.

12. The detector array (1) according to claim 6, wherein, At least one of the probe surfaces (3) has a rectangular outer perimeter.

13. The detector array (1) according to any one of claims 1-2, 5, 7-8, 10-12, wherein, The detector element (2) is suitable for detecting X-ray radiation.

14. The detector array (1) according to claim 3, wherein, The detector element (2) is suitable for detecting X-ray radiation.

15. The detector array (1) according to claim 4, wherein, The detector element (2) is suitable for detecting X-ray radiation.

16. The detector array (1) according to claim 6, wherein, The detector element (2) is suitable for detecting X-ray radiation.

17. The detector array (1) according to claim 9, wherein, The detector element (2) is suitable for detecting X-ray radiation.

18. The detector array (1) according to any one of claims 1-2, 5, 7-8, 10-12, 14-17, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

19. The detector array (1) according to claim 3, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

20. The detector array (1) according to claim 4, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

21. The detector array (1) according to claim 6, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

22. The detector array (1) according to claim 9, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

23. The detector array (1) according to claim 13, wherein, Each of the plurality of detector elements (2) includes a stacked dual-energy X-ray detector element, which includes a first detector component (2a) and a second detector component (2b) stacked on top of each other.

24. The detector array (1) according to any one of claims 1-2, 5, 7-8, 10-12, 14-17, and 19-23, wherein, Each of the plurality of detector elements (2) includes a scintillator.

25. The detector array (1) according to claim 3, wherein, Each of the plurality of detector elements (2) includes a scintillator.

26. The detector array (1) according to claim 4, wherein, Each of the plurality of detector elements (2) includes a scintillator.

27. The detector array (1) according to claim 6, wherein, Each of the plurality of detector elements (2) includes a scintillator.

28. The detector array (1) according to claim 9, wherein, Each of the plurality of detector elements (2) includes a scintillator.

29. The detector array (1) according to claim 13, wherein, Each of the plurality of detector elements (2) includes a scintillator.

30. The detector array (1) according to claim 18, wherein, Each of the plurality of detector elements (2) includes a scintillator.

31. The detector array (1) according to any one of claims 1-2, 5, 7-8, 10-12, 14-17, 19-23, 25-30, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

32. The detector array (1) according to claim 3, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

33. The detector array (1) according to claim 4, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

34. The detector array (1) according to claim 6, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

35. The detector array (1) according to claim 9, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

36. The detector array (1) according to claim 13, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

37. The detector array (1) according to claim 18, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

38. The detector array (1) according to claim 24, wherein the detector array (1) further comprises a support member, wherein, Each detector element (2) is detachably mounted on the support.

39. A radiographic examination system (20), the system (20) comprising: A radiation source (30) for generating a radiation beam (31), the radiation beam (31) comprising a beam of rays (33) forming a radiation plane (RP), the radiation beam (31) including a focal point (32); The detector array (1) according to any one of the preceding claims; A transmission device (40) for transmitting an item (50) to be inspected along a transmission path (T) transverse to the radiation plane (RP), the transmission path (T) being positioned between the radiation source (30) and the detector array (1). The detector array (1) is arranged such that the common plane (S) coincides with the radiation plane (RP), and the common focus (5) coincides with the focus (32).

40. The system (20) according to claim 39, wherein, The transmission device (40) includes a conveyor belt (41).

41. The system (20) according to claim 39 or 40, wherein, The radiation source (30) includes an X-ray source.

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