Backscatter X-ray System
By utilizing the backscattering effect and slit sensor design in the X-ray imaging system, the shortcomings of traditional X-ray imaging systems in non-destructive inspections are solved, and effective image formation and detection effects are achieved, suitable for cargo and full-body scanning.
Patent Information
- Application Number
- CN201880098899.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2018-11-06
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2038-11-06
AI Technical Summary
Traditional X-ray imaging systems are difficult to effectively utilize the backscattering effect when non-destructive examinations are required, and lack effective methods when there is only one side of the object for inspection.
A backscattered X-ray system is designed to scan narrow beams along the surface of the object through an X-ray source, and an image is formed using the Compton scattering effect to form an X-ray reflected from the object. The sensor is configured to distinguish backscattered X-rays at different points, including narrow Slits and multiple pixel lines or points to limit the angle of backscattered X-rays to achieve spatial resolution.
It realizes effective image formation in non-destructive inspections, is suitable for cargo scanning and full-body scanning, can detect non-metallic objects, and improves detection sensitivity and resolution.
Smart Images
Figure CN112912719B_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to a system for backscattering X-rays. [Background technology]
[0002] An X-ray detector may be a device for measuring the flux, spatial distribution, spectrum or other properties of X-rays. X-ray detectors can be used for many applications. One important application is imaging. X-ray imaging is a radiographic technique and can be used to reveal the internal structure of an opaque object of inhomogeneous composition, such as the human body. [Summary of the invention]
[0003] A backscatter X-ray system is disclosed herein, comprising: an X-ray source configured to scan an X-ray sheet across an object, wherein the X-ray sheet illuminates a line on a surface of the object; and a sensor configured to distinguish X-rays backscattered from different points along the line.
[0004] According to an embodiment, the X-ray source comprises a slit.
[0005] According to an embodiment, the X-ray film is scanned across the object by moving the slit or moving the object.
[0006] According to an embodiment, the X-ray film is not flat.
[0007] According to an embodiment, the wire is curved.
[0008] According to an embodiment, the X-rays from the X-ray source do not irradiate anywhere on the surface of the object except the line.
[0009] According to an embodiment, the sensor comprises a slit.
[0010] According to an embodiment, the slit is non-straight.
[0011] According to an embodiment, the sensor uses different parts of the sensor to collect X-rays backscattered from different points along the line.
[0012] According to an embodiment, the different portions are different lines on the sensor.
[0013] According to an embodiment, the different lines on the sensor are not straight.
[0014] According to an embodiment, the X-ray source comprises a slit and the portions are respective projections of the X-rays backscattered from the points onto the slit.
[0015] According to an embodiment, the sensor comprises a plurality of pixel lines.
[0016] According to an embodiment, the sensor comprises a plurality of pixels.
[0017] According to an embodiment, the sensor comprises a plurality of slits.
[0018] According to an embodiment, the sensor comprises a layer of material which is opaque to the backscattered X-rays.
[0019] According to an embodiment, the slit is configured to limit the angle at which the backscattered X-rays reach the sensor.
[0020] A cargo scanning or non-intrusive inspection (NII) system is disclosed herein, which includes any of the backscatter X-ray systems described above.
[0021] A whole body scanner system is disclosed herein, which comprises any one of the above-mentioned backscatter X-ray systems.
Brief Description of the Drawings
[0022] Figure 1 A backscatter X-ray system is shown schematically.
[0023] Figure 2 A backscatter X-ray system according to an embodiment is schematically illustrated.
[0024] Figure 3 Shows Figure 2 How the sensor of a backscatter x-ray system distinguishes between x-rays backscattered from different points on a line on the surface of an object.
[0025] Figure 4 The configuration of a sensor having a series of independent lines of pixels is shown.
[0026] Figure 5 The configuration of a sensor with a series of independent pixels is shown.
[0027] Fig. 6A A sensor according to an embodiment is schematically illustrated.
[0028] Figure 6B Schematically shows Fig. 6A Top view of the sensor in Figure 1.
[0029] Fig. 7A A sensor according to an embodiment is schematically illustrated.
[0030] Figure 7B Schematically shows Fig. 7A Top view of the sensor in Figure 1.
[0031] Figure 7C Schematically shows Fig. 7A Example of a slit in front of the sensor.
[0032] Figure 8 A cargo scanning or non-intrusive inspection (NII) system including a backscatter X-ray system as described herein is schematically illustrated according to an embodiment.
[0033] Fig. 9 A whole body scanner system comprising a backscatter X-ray system as described herein according to an embodiment is schematically shown. [Specific implementation method]
[0034] Backscatter X-ray is a type of X-ray imaging. Conventional X-ray imaging systems detect hard and soft materials based on changes in transmission through an object. In contrast, backscatter X-ray detects radiation reflected from an object. It has potential applications where less destructive inspection is required and can be used if only one side of an object is available for inspection.
[0035] Backscattered X-rays are based on the X-ray Compton scattering effect. Unlike X-ray imaging systems that rely on X-rays to transmit through an object, backscattered X-rays detect radiation reflected from an object and form an image. The backscatter pattern depends on the material properties.
[0036] Compton scattering is the inelastic scattering of photons by charged particles (e.g., electrons). Compton scattering results in a decrease in the energy (increase in wavelength) of a photon (e.g., an X-ray photon).
[0037] Figure 1 A backscatter X-ray system 100 is schematically shown. A narrow X-ray beam (e.g., beam 110 and beam 120) is scanned across an object 150. A collimator 115 may be used to generate the narrow X-ray beam. The beam may be scanned by moving (e.g., rotating) the collimator 115. As the beam is scanned across the object 150, individual points on the surface of the object 150 are illuminated by the beam, while the rest of the surface of the object 150 is not illuminated. Backscattered X-rays can only come from points illuminated by the beam. Therefore, any backscattered X-rays collected by the detector 130 at a given time can only come from points illuminated by the beam at that time. Because backscattered X-rays are not particularly directional, the detector 130 may be configured to collect backscattered X-rays propagating in many different directions. For example, the detector 130 may have a large area or be placed near the object. The detector 130 does not have to have a high spatial resolution. The spatial resolution of the backscatter X-ray system is achieved by the narrowness of the beam. In Figure 1In the example of , beam 110 illuminates point 113 on the surface of object 150. Backscattered X-rays 111 from point 113 can propagate in many directions, and at least some of the backscattered X-rays 111 are collected by detector 130. Beam 120 illuminates point 123 on the surface of object 150. Backscattered X-rays 121 from point 123 can propagate in many directions, and at least some of the backscattered X-rays 121 are collected by detector 130.
[0038] Figure 2 A backscatter X-ray system 200 according to an embodiment is schematically shown. At least one X-ray sheet 210 from an X-ray source 205 is scanned across an object 150. For example, a slit of the X-ray source 205 may be used to generate the X-ray sheet 210. The beam may be scanned by moving (e.g., rotating) the slit or moving the object 150. The term "sheet" here refers to a surface on which the X-rays 210 propagate substantially. The surface does not have to be flat. The X-rays 210 are on the surface if and only if the X-rays 210 illuminate one line 211 (straight or curved) on the object 150 at a time. When the X-ray sheet 210 is scanned across the object 150, each line 211 on the surface of the object 150 is illuminated by the X-rays 210, while the rest of the surface of the object 150 is not illuminated. Backscattered X-rays can only come from points illuminated by the X-rays 210, i.e., only from points along the lines 211 illuminated by the X-rays 210. Therefore, any backscattered X-rays collected by the sensor 230 at a given time can only come from a point along the line 211. The sensor 230 is configured to distinguish between X-rays backscattered from different points along the line 211. For example, the sensor 230 may include a slit 240. There may be multiple surfaces 220 passing through the slit 240. Each surface intercepts the object 150 at the line 221 and intercepts the sensor 230 at the line 222. Therefore, the backscattered X-rays collected at the line 222 can only come from the line 221 on the object 150. Because only the line 211 on the object 150 is illuminated, the backscattered X-rays collected at the line 222 can only come from the point 251 at the intersection of the line 221 and the line 211. The sensor 230 does not have to have a high spatial resolution along the line 222. The spatial resolution of the backscattered X-ray system is achieved by both the X-ray sheet 210 and the sensor 230. The backscattered X-rays collected at different lines 222 come from different points on the line 211.
[0039] Figure 3It is also shown how the sensor 230 distinguishes backscattered X-rays from different points on the line 211 on the surface of the object 250. In this example, the slit 240 is a straight slit because it is easier to explain how the system 200 works. The slit 240 does not necessarily have to be straight all the time. If the X-ray backscattered from the point 251A on the line 211 propagates in a direction in which such backscattered X-ray is not blocked by the slit 240, the backscattered X-ray can reach the sensor 230. That is, if the X-ray backscattered from the point 251A reaches the sensor 230, it is a surface 220A spanned by the point 251A and the slit 240. The X-ray backscattered from the point 251A can pass through the slit 240 to the line 231A on the sensor, where the line 231A is the projection of the X-ray backscattered from the point 251A on the slit 240. Similarly, if an X-ray backscattered from point 251B on line 211 propagates in a direction in which such backscattered X-ray is not blocked by slit 240, the backscattered X-ray can reach sensor 230. That is, if an X-ray backscattered from point 251B reaches sensor 230, it is a surface 220B spanned by point 251B and slit 240. The X-ray backscattered from point 251B can pass through slit 240 to reach line 231B on the sensor, where line 231B is a projection of the X-ray backscattered from point 251B onto slit 240. If an X-ray collected at line 231A and an X-ray collected at line 231B can be distinguished, then the backscattered X-rays from points 251A and 251B can be distinguished. Figure 3 In the example shown, lines 231A and 231B are both straight because slit 240 is straight and sensor 230 is flat. Figure 3 As shown in the example of , line 211 does not have to be straight.
[0040] Sensor 230 may be configured in various ways to differentiate between X-rays collected at different lines (eg, 231A and 231B).
[0041] For example, when the slit 240 is straight, X-rays backscattered from a point (e.g., 251A) on the line 211 (which is straight in this example) on the object 250 are on the plane (e.g., 220A) spanned by the point and the slit 240 and arrive at a straight line (e.g., 231A) on the sensor 230. Figure 4 The configuration of sensor 230 is shown, which has a series of independent pixel lines 261 extending in a direction parallel to a straight line (e.g., 231A) on the sensor. Each pixel line 261 can collect X-rays arriving at the pixel line independently of other pixel lines. That is, pixel line 261 can collect and distinguish X-rays backscattered from a series of points on line 211 on the surface of object 250.
[0042] For example, regardless of whether slit 240 is straight, X-rays backscattered from a point (e.g., 251A) on line 211 on object 250 (which may not be straight in this example) travel over the surface spanned by the point and slit 240 (e.g., 220A, which may not be flat in this example) and arrive at a line on sensor 230 (e.g., 231A, which may not be straight in this example). Figure 5 The configuration of the sensor 230 is shown with a series of independent pixels 262. Each pixel 262 can collect X-rays arriving at the pixel independently of other pixels. The sum of the X-rays collected by the pixels 262 through which the line 231A passes is the total amount of X-rays backscattered from point 251A that arrive at the sensor 230.
[0043] Fig. 6A The sensor 230 according to an embodiment is schematically shown. There may be a plurality of slits 240 in front of the sensor 230. The sensor 230 may have a material layer 610 that is opaque to backscattered X-rays, and the layer 610 may be configured to allow only scattered X-rays that pass through the slits 240 at a specific angle to reach the pixel line 261 or pixel point 262. The plurality of slits 240 may allow X-rays scattered from a plurality of points on the line 211 on the surface of the object 250 to be collected simultaneously. Figure 6B Schematically shows Fig. 6A Pixel lines 261 or pixel points 262 are shown in dotted lines to show their positions relative to the slits 240, because the pixel lines 261 or pixel points 262 are not visible from the top view.
[0044] Fig. 7A A sensor 230 according to an embodiment is schematically shown. There may be a plurality of slits 240 in front of the sensor 230. The sensor 230 may not have a material layer that is opaque to scattered X-rays. Due to the geometry of the slits 240, the slits 240 only allow scattered X-rays that pass through the slits 240 at a specific angle to reach the pixel line 261 or the pixel point 262. The plurality of slits 240 may allow X-rays scattered from a plurality of points on the line 211 on the surface of the object 250 to be collected simultaneously. Figure 7B Schematically shows Fig. 7A Pixel lines 261 or pixel points 262 are shown in dotted lines to show their positions relative to the slits 240, because the pixel lines 261 or pixel points 262 are not visible from the top view. Figure 7C An example of a slit 240 is schematically shown, where the slit 240 having a depth d and a width w blocks light exceeding an angle tan -1 (w / d) of scattered X-rays.
[0045] Figure 8A cargo scanning or non-intrusive inspection (NII) system including a backscatter X-ray system 200 as described herein is schematically shown. The NII system can be used to inspect and identify cargo in a transportation system such as a shipping container, a vehicle, a ship, luggage, etc. X-rays emitted from an X-ray source 205 can be backscattered from an object 250 (e.g., a shipping container, a vehicle, a ship, etc.) and projected to a sensor 230. Different internal structures of the object 250 can backscatter the X-rays differently. The sensor 230 forms an image by detecting the intensity distribution of the backscattered X-rays and / or the energy of the backscattered X-ray photons.
[0046] Fig. 9 A full body scanner system including a backscatter X-ray system 200 described herein is schematically shown. The full body scanner system can detect objects on the human body for security inspection without physically removing clothing or making physical contact. The full body scanner system may be able to detect non-metallic objects. X-rays emitted from an X-ray source 205 can be backscattered from an object 250 (e.g., a person being screened) and projected to a sensor 230. Different parts of the object 250 can backscatter X-rays differently. The sensor 230 forms an image by detecting the intensity distribution of the backscattered X-rays. The backscatter X-ray system 200 can be configured to scan a person in a linear or rotational direction.
[0047] Although various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.
Claims
1. A backscatter X-ray system, comprising: an X-ray source configured to scan an X-ray film across an object, wherein the X-ray film illuminates a first line on a surface of the object; a sensor configured to distinguish X-rays backscattered from different points along the first line, the sensor comprising a second slit, wherein the sensor uses different portions of the sensor to collect X-rays backscattered from different points along the first line, wherein the portions are corresponding projections of the X-rays backscattered from the points onto the second slit, and the different portions are different second lines on the sensor, The sum of the X-rays collected by the second line of the sensor is the total amount of X-rays that are backscattered from the point on the first line corresponding to the second line and reach the sensor.
2. The system according to claim 1, wherein: The X-ray source includes a first slit.
3. The system according to claim 2, wherein: The X-ray film is scanned across the object by moving the first slit or moving the object.
4. The system according to claim 1, wherein: The X-ray film is not flat.
5. The system of claim 1, wherein the first wire is curved.
6. The system according to claim 1, wherein: X-rays from the X-ray source do not irradiate anywhere on the surface of the object except the first line.
7. The system according to claim 1, wherein: The second slit is not straight.
8. The system according to claim 1, wherein: The different second line on the sensor is not straight.
9. The system according to claim 1, wherein: The sensor includes a plurality of pixel lines.
10. The system according to claim 1, wherein: The sensor includes a plurality of pixels.
11. The system according to claim 1, wherein: The sensor includes a plurality of second slits.
12. The system of claim 1, wherein: The sensor comprises a layer of material that is opaque to the backscattered X-rays.
13. The system of claim 1, wherein: The second slit is configured to limit an angle at which the backscattered X-rays reach the sensor.
14. A cargo scanning system comprising the backscatter X-ray system according to claim 1.
15. A non-invasive inspection system comprising the backscatter X-ray system according to claim 1.
16. A whole body scanner system comprising the backscatter X-ray system according to claim 1.