Field of Invention

The invention relates but is not limited to a matrix of detectors configured to be used in a system for inspecting cargo using inspection radiation. The invention also relates to a method of manufacturing such a matrix of detectors.

Background

The optimal number of columns in a matrix of detectors depends on the type of cargo inspection system on which the matrix is to be mounted (whether the system is a portal, a mobile system or a gantry, for example) and on the desired scanning speed.

The matrix of detectors may be made of a matrix of scintillating crystal glued on a corresponding matrix of photodiodes.

The respective matrices of photodiodes for matrices with different numbers of columns are different. Similarly, the respective matrices of scintillating crystal for matrices with different numbers of columns are different. Each of the different matrices of photodiodes and each of the different matrices of scintillating crystal are manufactured for the different types of matrices of detectors, depending of the required numbers of columns. Summary of Invention

Aspects and embodiments of the invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein.

Brief Description of Drawings Embodiments of the present disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1A schematically illustrates an elevated view of an example matrix of detectors according to the disclosure, viewed in an in-depth direction (OZ) of propagation of the inspection radiation; Figure 1 B schematically illustrates a top view of the example matrix of detectors of

Figure 1 A, with a first offset;

Figure 2 schematically illustrates a top view of another example matrix of detectors, with a second offset; Figure 3 schematically illustrates a top view of another example matrix of detectors, comprising four columns with a plane of symmetry;

Figure 4A schematically illustrates a top view of another example matrix of detectors, comprising four columns with every column being offset with respect to an adjacent column;

Figure 4B schematically illustrates a top view of another example matrix of detectors, comprising five columns with every column being offset with respect to an adjacent column;

Figure 5 schematically illustrates a top view of another example matrix of detectors, comprising three columns with two columns not being offset with respect to each other;

Figure 6 schematically illustrates a top view of another example matrix of detectors, comprising four columns with a plane of symmetry, with detector modules comprising a plurality of stacked detectors; and

Figure 7 schematically illustrates a flowchart of an example method for manufacturing a matrix of detectors according to any aspect of the disclosure.

In the figures, similar elements bear identical numerical references.

Specific Description of Example Embodiments Overview

Embodiments of the disclosure provide a matrix of detectors for an inspection system for inspecting cargo using inspection radiation. The matrix of detectors may comprise a plurality of columns extending in a longitudinal direction substantially perpendicular to a scanning direction. Each column comprises a plurality of modules for receiving the inspection radiation. The plurality of columns are adjacent to each other in a lateral direction substantially parallel to the scanning direction, to form the matrix of detectors. In the plurality of columns, at least two columns are offset with respect to each other in an in- depth direction substantially perpendicular to both the lateral direction and the longitudinal direction.

In embodiments of the disclosure, the offset enables the use of a scalable architecture for the matrix of detectors. In embodiments of the disclosure, the offset enables increasing or decreasing the number of columns, using identical or similar columns and/or identical or similar detector modules regardless of the number of columns. In embodiments of the disclosure, the offset enables increasing or decreasing the number of columns without using matrices of photodiodes or matrices of scintillating crystal dedicated to a given number of columns. The scalability enabled by embodiments of the disclosure enables relatively low manufacturing costs.

Detailed description of example embodiments

Figures 1 A and 1 B schematically illustrate an example matrix 1 of detectors configured to be used in a system for inspecting cargo using inspection radiation.

In Figures 1A and 1 B, the matrix 1 of detectors comprises a plurality n (n>2, with n=2 in Figures 1 A and 1 B) of columns 2 of detector modules 3.

As illustrated in Figures 1A and 1 B, the detector modules 3 of each column 2 extend along a substantially longitudinal direction LONG. In Figures 1 A and 1 B, the longitudinal direction LONG is substantially parallel to the direction (OY).

Each detector module 3 comprises an inspection surface 4 configured to receive the inspection radiation 5. In Figures 1A and 1 B, the inspection surfaces 4 are substantially parallel to the plane (XOY).

The plurality n of columns 2 of detector modules 3 are adjacent to each other in a lateral direction LAT substantially perpendicular to the longitudinal direction LONG and substantially parallel to the inspection surfaces 4 of the detector modules 3. In Figures 1A and 1 B, the lateral direction LAT is substantially perpendicular to the direction (OY) and substantially parallel to the plane (XOY). In Figures 1A and 1B, the lateral direction LAT is substantially parallel to the direction (OX). As illustrated in Figures 1A and 1 B, the plurality n of columns 2 comprises at least two columns 2 being offset with respect to each other in an in-depth direction DEPTH substantially perpendicular to both the lateral direction LAT and the longitudinal direction LONG.

In Figures 1A and 1 B, the two columns 2 are offset by an offset d with respect to each other in the direction (OZ) substantially perpendicular to both the lateral direction LAT and the longitudinal direction LONG. In Figures 1A and 1 B, the offset d is measured between the inspection surfaces 4 of one column 2 and the inspection surfaces 4 of another, offset column 2. As explained in greater detail below, the offset d in the in-depth direction DEPTH may enable at least partial overlap of the columns in the lateral direction LAT. The at least partial overlap of the columns in the lateral direction LAT may enable the use of identical or similar columns and/or identical or similar detector modules in a scalable architecture for the matrix of detectors.

As illustrated in the Figures, in some embodiments, each column 2 comprises at least one printed circuit board 6.

In the example of Figures 1 A and 1 B, the at least one printed circuit board 6 is adjacent to the detector modules 3 of the column 2, and extends in a plane substantially perpendicular to the inspection surfaces 4 of the detector modules 3 of the column 2. In the example of Figures 1A and 1B, the at least one printed circuit board 6 extends in a plane substantially parallel to the plane (YOZ) which is perpendicular to the inspection surfaces 4 of the detector modules 3 of the column 2.

In the example of Figure 4A, the at least one printed circuit board 6 is at least partly adjacent to the detector modules 3 of the column 2, and extends in a plane substantially parallel to the inspection surfaces 4 of the detector modules 3 of the column 2. In the example of Figure 4A, the at least one printed circuit board 6 extends in a plane substantially perpendicular to the plane (YOZ) which is perpendicular to the inspection surfaces 4 of the detector modules 3 of the column 2. In the example of Figure 4B, one printed circuit board 6 extends in a plane substantially parallel to the inspection surfaces 4 of the detector modules 3 of the column 2 (in a plane substantially perpendicular to the plane (YOZ), and two printed circuit boards 6 extend in a plane substantially perpendicular to the inspection surfaces 4 of the detector modules 3 of the column 2 (in a plane substantially parallel to the plane (YOZ)).

Other configurations and combinations of the positions of the circuit boards 6 are envisaged. As illustrated in the Figures, each detector module 3 comprises at least one detector 30 configured to interact with the inspection radiation. As illustrated in the Figures, each detector module 3 comprises at least one sensor 7 configured to detect a response of the detector 30 to interaction with the inspection radiation 5. As illustrated in the Figures, the at least one sensor 7 may be located between the at least one printed circuit board 6 and the at least one detector 30.

As illustrated in Figures 1A and 1 B, the offset d in the in-depth direction DEPTH enables the partial overlap l of the columns 2 in the lateral direction LAT, and enables the use of identical columns and/or identical detector modules in a scalable architecture for the matrix of detectors. As illustrated in Figures 1 A and 1 B, the partial overlap l of the columns 2 in the lateral direction LAT is such that a back surface 8 of the detector 30, opposed to the inspection surface 4, of one column 2 at least partially or entirely covers, in the lateral direction LAT, the at least one printed circuit 6 and the at least one sensor 7 of another column 2. In Figures 1A and 1 B, the offset d and the overlap l are such that the detector 30 of one column 2 does not overlap, in the lateral direction LAT, the detector 30 of another column 2.

Figures 1 B and 2 illustrate examples of the offset d such that 0 < d £ D, with D being a dimension of the detector modules 3 in the in-depth direction DEPTH.

Figure 6 illustrates an example of the offset d such that:

D < d

Typical detector modules for high energy cargo inspection systems may be made of high density crystals with D smaller than 5cm. Typical distances L between an inspection radiation source and the matrix of detectors are comprised between about 5m and about 15m. The dimension D of the detector modules may be negligible compared to the distances L for a range of d and in some examples the offset d may be such that:

0 < d £ SD, with D being a dimension of the detector modules 3 in the in-depth direction DEPTH. Figures 1 B and 2 also illustrate that the matrix 1 may comprise an even number of columns 2.

As explained in greater detail below, the offset d enables increasing or decreasing the number of columns, using identical or similar columns and/or identical or similar detector modules regardless of the number of columns. As illustrated in Figure 3, the matrix 1 may comprise an even number n of columns 2 (n=4 in Figure 3) and may have a central plane of symmetry P. In Figure 3 the central plane of symmetry P may be substantially parallel to the in-depth direction DEPTH. In Figure 3 the plurality n comprises four columns, but other numbers of columns may be envisaged, such as six, eight or ten columns as non-limiting examples.

Figures 4A and 4B schematically illustrate examples of matrices 1 where each column 2 of the plurality of columns 2 is offset with respect to an adjacent column in the plurality of columns. Figures 4B and 5 schematically illustrate examples of matrices 1 comprising an odd number of columns (five columns in Figure 4B and three columns in Figure 5 - other numbers may be envisaged).

As illustrated in Figure 5, when the plurality of columns of detector modules comprises at least three columns, the plurality of columns 2 may comprise at least two columns of detectors pi and p ₂ not being offset with respect to each other in the in-depth direction, while p ₂ and p ₃ are offset with respect to each other in the in-depth direction.

In Figures 1A, 1B, 2, 3, 4A, 4B and 5, each detector module 3 comprises a single detector 30 in a direction substantially parallel to the in-depth direction DEPTH.

As illustrated in Figure 6, in some examples each detector module 3 may comprise a plurality of detectors 30 stacked in a direction substantially parallel to the in-depth direction DEPTH. Such detector modules may be advantageously used e.g. for material discrimination.

In Figures 1 B and 2, each detector 30 comprises e.g. two sensors 7. In Figures 3 and 5, each detector 30 comprises e.g. four sensors 7. In Figures 4A, 4B and 6, each detector 30 comprises e.g. one sensor 7. Other numbers of sensors are envisaged.

In some examples, each detector 30 comprises a scintillator configured to re-emit light in response to interaction with the inspection radiation, and the at least one sensor 7 comprises at least one photodiode configured to detect the re-emitted light.

As illustrated in Figure 7, the disclosure also relates to a method 100 of manufacturing a matrix of detectors according to any aspect of the disclosure. The method 100 comprises: providing, at S1 , a plurality of columns of detector modules, the detector modules of each column extending along a substantially longitudinal direction, each detector module comprising an inspection surface configured to receive inspection radiation; and placing, at S2, the provided plurality of columns adjacent to each other in a lateral direction substantially perpendicular to the longitudinal direction and substantially parallel to the inspection surfaces of the detector modules such that the plurality of columns of detector modules comprises at least two columns of detector modules being offset with respect to each other in an in-depth direction substantially perpendicular to both the lateral direction and the longitudinal direction.