RADIATION PROTECTION DEVICE FOR INSPECTION FACILITIES

Abstract

A radiation protection device for an opening for inspection objects on a radiation tunnel is provided. The radiation protection device is formed from a plurality of radiation protection curtains arranged one behind the other at a distance in a transport direction, wherein a first radiation protection curtain includes a first shielding radiation protection curtain section covering only a first area of the opening and second shielding radiation protection curtain sections of at least one second radiation protection curtain arranged behind the first radiation protection curtain in the transport direction cover the area of the opening not covered by the first radiation protection curtain.

Claims

1. A radiation protection device for an opening for inspection objects on a radiation tunnel of an inspection apparatus, wherein the radiation protection device is formed from a plurality of radiation protection curtains arranged one behind the other at a distance in a transport direction of the radiation tunnel, wherein a first radiation protection curtain comprises a first shielding radiation protection curtain section covering only a first area of the opening, and wherein second shielding radiation protection curtain sections of at least one second radiation protection curtain arranged behind the first radiation protection curtain in the transport direction cover the area of the opening not covered by the first radiation protection curtain.

2. The radiation protection device according to claim 1, wherein the first radiation protection curtain covers the opening starting from an upper edge of the opening opposite to a transport plane defined by a transport system for the inspection objects, with the first shielding radiation protection curtain section having a first length that corresponds to only a part of the clearance height of the opening.

3. The radiation protection device according to claim 1, wherein the shielding radiation protection curtain sections of two radiation protection curtains following each other in the transport direction through the radiation tunnel overlap in the longitudinal direction by an overlapping length with respect to the transport direction.

4. The radiation protection device according to claim 1, wherein two successive radiation protection curtains are arranged at a distance from one another in the transport direction through the radiation tunnel.

5. The radiation protection device according to claim 1, wherein a second radiation protection curtain comprises at least the second shielding radiation protection curtain section and a non-shielding support section.

6. The radiation protection device according to claim 5, wherein the non-shielding support section is connected to the second shielding radiation protection curtain section by at least one of the following connection techniques from the group consisting of gluing, clamping, riveting, and sewing.

7. The radiation protection device according to claim 1, wherein in a first and/or second shielding radiation protection curtain section at least the core comprises a material with a high atomic number.

8. The radiation protection device according to claim 1, wherein a first or second radiation shielding curtain is formed of individual radiation shielding elements each having a strip shape, and wherein a strip length is greater than a strip width and a strip thickness is substantially smaller than the strip width.

9. A radiation protection element for a radiation protection device, wherein the radiation protection element has a shielding section and a non-shielding support section in its longitudinal direction, the non-shielding support section dimensioned in this way, in that, when the radiation protection element is arranged on the radiation protection device as intended, it extends in the region of an opening to be covered by means of the radiation protection device and carries the shielding section, which in turn extends completely in the region of the opening to be covered by means of the radiation protection device when the radiation protection element is arranged on the radiation protection device as intended.

10. The radiation protection element according to claim 9, wherein the support section is connected to the shielding section by at least one of the following joining techniques from the group consisting of gluing, clamping, riveting, and sewing.

11. The radiation protection element according to claim 9, wherein at least the core of the shielding section comprises a material with a high atomic number.

12. An inspection apparatus having at least one radiation protection device according to claim 1, wherein the radiation protection device is mounted at the opening of the radiation tunnel of the inspection apparatus, and the opening is an entrance of the radiation tunnel or an exit of the radiation tunnel.

13. The inspection apparatus according to claim 12, wherein radiation protection elements of the first curtains are attached to the inspection apparatus at one end of the first shielding radiation protection curtain section by at least one joining technique from the group consisting of: screwing, clamping, and riveting.

14. The inspection apparatus according to claim 12, wherein radiation protection elements of the second curtains are attached at one end of the support section to the inspection apparatus by at least one joining technique from the group consisting of: screwing, clamping, and riveting.

15. A method for retrofitting a radiation protection device on an X-ray inspection apparatus, wherein an existing radiation protection device is replaced by a radiation protection device according to claim 1.

16. The radiation protection device according to claim 3, wherein the overlapping length of the overlap is greater than or equal to the distance between the successive radiation protection curtains.

17. The radiation protection device according to claim 4, wherein a minimum distance D.sub.min of the two successive radiation protection curtains is greater than or equal to
D.sub.min=√{square root over (2*L1*ΔL−ΔL.sup.2)}, where L1 is the total length of the shielding radiation protection curtain section of the preceding radiation protection curtain and ΔL is the length of an overlap of the radiation protection sections of the two successive radiation protection curtains.

18. The radiation protection device according to claim 4, wherein a maximum distance D.sub.max of two consecutive radiation protection curtains is less than or equal to
D.sub.max=(ΔL*G)/(LH−L2), where L2 is the length of the shielding radiation protection curtain section of the following radiation protection curtain, G is the distance of the following radiation protection curtain from a radiation plane of a radiation fan generated by a radiation generator, ΔL is the length of an overlap of the shielding radiation protection sections of the two successive radiation protection curtains, and LH is the clearance height of the opening of the radiation tunnel.

19. The radiation protection device according to claim 7, wherein the material with a high atomic number contains or consists of at least one of the following materials: pure lead, lead oxide, tin, tin oxide, lead vinyl, lead rubber, barium, samarium, tungsten, or a mixture of some or all of these materials.

20. The radiation protection element according to claim 9, wherein the material with a high atomic number comprises or consists of at least one of the following materials: pure lead, lead oxide, tin, tin oxide, lead vinyl, lead rubber, barium, samarium, tungsten, or a mixture of some or all of these materials.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Further advantages, features and details of the disclosure result from the following description, in which embodiments of the disclosure are described in detail by reference to the drawings. The features mentioned above and the features further elaborated here may each be used individually or in combination with each other. Functionally similar or identical parts or components are partly provided with the same reference signs. The terms “left”, “right”, “top” and “bottom” used in the description of the design examples refer to the drawings in an alignment with normally legible figure designation or normally legible reference signs. The embodiments shown and described are not to be understood as exhaustive but are of an exemplary nature to explain the disclosure. The detailed description is intended to provide information for the skilled person. Therefore, known structures and processes are not shown or explained in detail in the description in order not to make the understanding of the present description difficult.

[0057] FIG. 1 shows a known X-ray inspection apparatus in a lateral sectional view with a radiation protection device consisting of several radiation protection elements.

[0058] FIG. 2 shows a lateral cross-section of an example embodiment of a radiation protection device according to the disclosure to illustrate the principle.

[0059] FIG. 3 shows a first use case of an example embodiment of a radiation protection device according to the disclosure in a lateral sectional view and an inspection object with a height such that the inspection object must displace the first radiation protection curtain in order to pass through it.

[0060] FIG. 4 shows a second use case of the example embodiment of the radiation protection device according to the disclosure of FIG. 3 in a lateral sectional view and an inspection object with a height such that the inspection object can be transported under the first radiation protection curtain.

DETAILED DESCRIPTION

[0061] FIG. 2 shows a lateral cross-section of an example embodiment of a radiation protection device according to the disclosure to illustrate the principle. A radiation protection device 30 is installed at an opening E, A for inspection objects 23 at a radiation tunnel 12 of an inspection apparatus. The radiation protection device 30 consists of several radiation protection curtains 30a, 30b arranged one behind the other at a distance D in a transport direction TR of the radiation tunnel 12. In the example shown, the radiation protection device 30 consists in total of two radiation protection curtains 30a, 30b, a first radiation protection curtain 30a and a second radiation protection curtain 30b.

[0062] The first radiation protection curtain 30a has a first shielding radiation protection curtain section 30a-1, which is dimensioned so that only a first area of the opening E, A is covered. The second shielding radiation protection curtain section 30b-1 of one second radiation protection curtain 30b arranged behind the first radiation protection curtain 30a in transport direction TR is dimensioned in such a way that it covers the area of the opening E, A not covered by the first radiation protection curtain 30a.

[0063] The radiation protection device 30 is a cover of the opening E, A at the radiation tunnel 12 that can be passed by inspection objects. Thus, the inspection object 23 can pass through the radiation protection device and can be transferred into or out of the radiation tunnel 12. The cover serves to shield the radiation tunnel 12 to the outside by preventing ionizing radiation in an impermissible dose from escaping from the radiation tunnel 12 through the opening E, A.

[0064] FIG. 2 shows that the first radiation curtain 30a covers the opening E, A with the first shielding radiation curtain section 30a-1 over a first length L1 starting from the upper edge of the opening E, A opposite to a transport level TE defined by a transport system 20, e.g. a conveyor belt. The first length L1 represents only a part of the clearance height LH of the opening E, A. This is the first radiation protection curtain 30a cannot completely shield the opening E, A alone.

[0065] The two shielding radiation protection curtain sections 30a-1 and 30b-1 of the two radiation protection curtains 30a and 30b, which follow each other in the transport direction TR through the radiation tunnel 12, overlap or overlay in longitudinal direction LR by an overlapping length ΔL with respect to the transport direction TR. The overlapping length ΔL of the overlap is essentially determined as at least as large as the distance D between the radiation protection curtains under consideration, i.e. ΔL greater than or equal to D.

[0066] The two consecutive radiation protection curtains 30a and 30b are arranged at the predetermined distance D to each other in the transport direction TR through the radiation tunnel 12. The distance D is approximately the length ΔL of the overlapping section of the shielding radiation protection curtain sections 30a-1 and 30b-1.

[0067] The minimum distance D.sub.min of the two consecutive curtains 30a, 30b is greater than or equal to

D.sub.min=√{square root over (2*L1*ΔL−ΔL.sup.2)},

where L1 is the total length of the shielding radiation protection curtain section 30a-1 of the preceding radiation protection curtain 30a and ΔL is the length of the overlap of the radiation protection sections 30a-1, 30b-1 of the two successive radiation protection curtains 30a, 30b

[0068] The maximum distance D.sub.max of the two consecutive radiation protection curtains 30a, 3b is less than or equal to

D.sub.max=(ΔL*G)/(LH−L2),

[0069] where L2 is the length of the shielding radiation protection curtain section of the following radiation protection curtain 30b, G is the distance of the following radiation protection curtain 30b to the radiation fan 26 generated by the radiation generator 18, ΔL is the length of the overlap of the shielding radiation protection sections 30a-1, 30b-1 of the two consecutive radiation protection curtains 30a, 30b and LH is the clearance height of the opening E, A of the radiation tunnel 12.

[0070] The second radiation protection curtain 30b consists of the second shielding radiation protection curtain section 30b-1 and a non-shielding support section 30b-2. In the example shown, the non-shielding support section 30b-2 is formed from a foil as support material. Other materials, such as a fabric or a woven fabric, can also be used as support materials. In the example embodiment, the support material is a foil.

[0071] Compared to the material of the shielding radiation protection curtain section 30b-1, the foil as support material has a lower weight per unit length and, compared to the material of the shielding radiation protection curtain section 30b-1, a higher flexibility, i.e. a lower bending resistance moment W.

[0072] To connect the radiation protection curtain section 30b-1 with the foil, the foil is applied to both sides of the shielding radiation protection curtain section 30b-1 and extends one end of the shielding radiation protection curtain section 30b-1, which is located at the top with respect to the transport plane TE, to form the support section 30b-2. This is two layers of foil FS1, FS2 sandwich the shielding radiation protection curtain section 30b-1.

[0073] The foils FS1, FS2 consist of poly(p-phenylene terephthalamide) (PPTA), poly(m-phenylene isophthalamide) (PMPI), thermoplastic elastomer (TPC-ET) or similar, e.g. made of Kevlar or Hytrel, all materials which have a lower coefficient of friction than the surface of the shielding radiation protection curtain sections 30a-1, 30b-1. Thereby it is ensured that the foils FS1, FS2 do not adhere to an inspection object 23 and/or an adjacent shielding radiation protection curtain section 30b-1. In addition, the foils FS1, FS2 have a sufficiently high stiffness so that they do not twist during operation.

[0074] In the example, the support section 30b-2 is connected to the second shielding radiation protection curtain section 30b-1 by the sandwich-like bonding, but can alternatively or additionally also be connected by riveting or the like.

[0075] The radiation protection curtains 30a and 30b shown in FIG. 2 in a lateral cross-sectional view consist of individual radiation protection elements arranged next to each other essentially transverse to the transport direction TR. These radiation protection elements, which are not shown in detail, have the form of tabs, lamellas or strips. This is the length of a radiation protection element is greater than its width and the thickness or thickness is considerably smaller than the width. The length is defined in the longitudinal direction LR. The width is essentially perpendicular to the direction of transport TR. The thickness d (or thickness) is defined essentially in the direction of transport TR. The width may be about 90 mm, but can also be up to a maximum of 120 mm and a minimum of 10 mm. The thickness d in transport direction TR may be typically about 2.5 mm, this value being based on lead as shielding material, i.e. if a different material or mixture of materials is used, the thickness d must be adjusted accordingly. In other words, the thickness d may be set so that it corresponds to a predetermined lead equivalent value which is required to achieve the desired shielding of ionizing radiation. The shielding sections of radiation protection elements contain or consist at least in their core of at least one material suitable for shielding ionizing radiation, such as pure lead (powder), lead oxide, tin, tin oxide, lead vinyl, lead rubber, barium and samarium, tungsten or a mixture of some or all of these materials.

[0076] A radiation shielding element for the second radiation curtain 30b of the radiation protection device 30 shown in the Figures has in its longitudinal direction LR the shielding section 30b-1 and the non-shielding support section 30b-2 The non-shielding support section 30b-2 is dimensioned so that, when the radiation shielding element is arranged as intended to form the radiation protection device 30, it runs in the area of the opening E, A to be covered by the radiation protection device 30 and supports the shielding section 30b-1. The shielding section 30b-1, in turn, runs completely in the area of the opening E, A still total to be covered by the radiation protection device 30 when the radiation protection element is arranged as specified.

[0077] As explained above in connection with the first and second radiation protection curtains 30a, 30b, the non-shielding support section 30b-2 in the design example is made of a foil.

[0078] Firstly, the material and/or dimensions of the foil are selected so that the support section has a lower weight per unit length compared to the shielding section 30b-1, thus the radiation shielding element is lighter compared to a conventional radiation shielding element which is dimensioned to cover the entire opening E, A.

[0079] Alternatively, or additionally, the material and/or dimensions of the foil are selected so that the support section 30b-2 has a higher flexibility compared to the shielding section 30b-1.

[0080] In the version shown in FIG. 2, one foil FS1 and one foil FS2 are applied to each side of the shielding section 30b-1 in transport direction TR. Each of the foils FS1, FS2 continues at one end E1 of the shielding section 30b-1 to form the support section 30b-2. In other words, the two foils FS1 and FS2 sandwich the shielding section 30b-1 to protect the shielding section 30b-1.

[0081] It should be noted that only one of the foils FS1, FS2 can be applied or attached to only one of the two sides of the shielding section 30b-1. This one film FS1 or FS2 would then also continue at one end E1 of the shielding section 30b-1 to form the support section 30b-2 at the required length.

[0082] As noted above, the foils FS1 and FS2 are made of a material that has a lower coefficient of friction than the surface of the shielding sections 30a-1, 30b-1, so that the foil does not adhere to an inspection object and/or an adjacent shielding section 30a-1 or 30b-1.

[0083] In order to prevent the foil(s) FS1, FS2 from twisting during operation, the foil(s) is (are) made of a material and/or designed with a thickness so that a sufficiently high stiffness is achieved. For example, the film is made of poly(p-phenylene terephthalamide) (PPTA), poly(m-phenylene isophthalamide) (PMPI), thermoplastic elastomer (TPC-ET) or similar.

[0084] It should be noted that the support section 30b-2 can also be made of another material.

[0085] The support section 30b-2 is connected to the shielding section 30b-1 at the end E1. In the implementation shown, the connection is ensured by the fact that the two foils FS1 and FS2 sandwich the shielding section 30b-1 and thus create a firm connection. However, it is possible to make the connection additionally, or alternatively, especially with other materials for the support section 30b-2, for example by using an adhesive and/or by clamping and/or by riveting.

[0086] The shielding section 30a-1 of the radiation protection element has at least one core which consists of or at least contains a material which dampens ionizing radiation. Such materials are for example pure lead, lead oxide, tin, tin oxide, lead vinyl, lead rubber, barium, samarium.

[0087] FIG. 3 shows a first use case of an example embodiment of a radiation protection device 30 according to the disclosure in a lateral sectional view and an inspection object 24 with a height such that the inspection object 24 must displace the first radiation protection curtain 30a in order to pass it.

[0088] The X-ray inspection apparatus 10 of FIGS. 3 and 4 can, for example, be used for the non-destructive inspection of baggage as inspection objects at an access to a security area at an airport. A radiation tunnel 12 of the inspection apparatus 10 is essentially an ionizing radiation shielding tube into which a transport system 22, consisting of individual partial transport units 22-1, 22-2, 22-3, for example belt conveyors, rope belt conveyors or similar, can introduce inspection objects 24, 25 at an opening E of a first open end in a transport direction TR into the radiation tunnel 12. The opening E at the first open end could serve both as entrance and exit of radiation tunnel 12, in which case the transport direction TR would have to be reversed in order to discharge the inspection object 24, 25.

[0089] Usually, and thus in the shown inspection apparatus 10, opening E at the first open end of radiation tunnel 12 serves as entrance to radiation tunnel 12 and a second opening A at a second open end serves as exit of radiation tunnel 12. In this configuration, inspection objects 24, 25 are conveyed through radiation tunnel 12 in transport direction TR, so that a continuous throughput at inspection apparatus 10 can be achieved.

[0090] The radiation tunnel 12 has a radiation section 16, in which the inspection objects 24, 25 are non-destructively X-rayed by means of ionizing radiation, in the example X-ray radiation. For this purpose, at least one radiation source 18, here an X-ray tube, as well as at least one detector arrangement 20 directed at the radiation emitted by the radiation source 18, here X-ray radiation, is arranged in radiation section 16.

[0091] The inspection apparatus 10 has a radiation protection device 30 at the entrance and at the exit of the radiation tunnel 12. The radiation protection device 30 consists of a first radiation protection curtain 30a and a second radiation protection curtain 30b. Between the two radiation protection curtains 30a, 30b there is the radiation area 16 with the at least one radiation source 18 and the detector arrangement 20 aligned to it.

[0092] The transport system 22, consisting of the three conveyor units 22-1, 22-2, 22-3, transports an inspection object 24, 25 through the radiation tunnel 12. The inspection object 24 in FIG. 1 is, for example, a suitcase. The inspection object 25 in FIG. 2 is, for example, a tray for smaller inspection objects (not shown), such as items of clothing or small appliances, such as a laptop. When passing through the radiation tunnel 12, the inspection objects 24, 25 are irradiated or shone through line by line by a radiation fan 26 generated by the radiation source 18 and the intensity of the radiation not absorbed by the inspection object 24, 25 is recorded as inspection data by means of the detector array 20.

[0093] In order to guarantee the reduction of the ionizing radiation emerging from the X-ray inspection apparatus 10 in accordance with the legal requirements, shielding sections of the radiation protection elements of the radiation protection curtains 30a, 30b each consist of a material suitable for shielding ionizing radiation, which has a thickness required for the desired shielding dimension (shielding factor).

[0094] In FIG. 3, the case as inspection object 24 stands on the transport level TE and has a height such that it does not fit under the first radiation protection curtain 30a. This means that the inspection object 24 must displace both the first radiation curtain 30a and the second radiation curtain 30b located behind it in the transport direction TR in order to be fed into the radiation tunnel 12 or discharged at the end.

[0095] FIG. 4 shows a second use case of the example embodiment of the radiation protection device of FIG. 3 according to the disclosure in a lateral sectional view and an inspection object with a height such that the inspection object can be transported under the first radiation protection curtain.

[0096] In FIG. 4, the tray as inspection object 25 stands on the transport level TE and has a height such that it fits under the first radiation protection curtain 30a. This means that the inspection object 25 does not have to displace the first radiation protection curtain 30a, but only the second radiation protection curtain 30b located behind it in the transport direction TR in order to be fed into radiation tunnel 12 or discharged at the end. Due to the fact that the second radiation protection curtain is considerably lighter than a single conventional radiation protection curtain that is dimensioned to cover the entire opening E, A at the entrance or at the exit of radiation tunnel 12, the small inspection object 25 can displace the second radiation protection curtain 30b more easily.

[0097] Thus, jams of smaller and often correspondingly lighter inspection objects at the radiation protection device 30 are avoided. Also, the alignment of smaller inspection objects on the transport system 22 is not changed, so that in inspection apparatuses in which different X-ray principles are used one after the other, an assignment of the inspection data is possible without any problems.