System for radiographically inspecting an object using backscattered radiation and related method

• US 4,974,247 A
• Filed: 11/24/1987
• Issued: 11/27/1990
• Est. Priority Date: 11/24/1987
• Status: Expired due to Fees

• Current Assignee: Boeing Company TE
• Original Assignee: The Boeing Co.
• Inventors: Friddell, Kenneth D.
• Primary Examiner(s): Fields, Carolyn E.
• Assistant Examiner(s): Porta, David P.
• Application Number:
  US07/124,625
• Time in Patent Office: 1,099 Days
• Field of Search: 378/44, 378/45, 378/48, 378/46, 378/47, 378/86, 378/87-89, 378/90
• US Class Current: 378/90
• CPC Class Codes: G01N 23/203 Measuring back scattering

Abstract

A system and related method are provided for radiographically inspecting an object, located in a radiation path at an inspecting location, using backscattered radiation to obtain a radiographic representation of the object. Radiation, from a source, is transmitted to the selected location. A portion of the transmitted radiation passes through the object and is backscattered by an illuminator to a radiation detecting device. Another portion of the transmitted radiation interacts with and is backscattered by the object to the detecting device. The detecting device generates response signals in response to both portions of the backscattered radiation. The response signals are used to obtain the radiographic representation of the object.

Claims

1. A system for radiographically inspecting an object disposed at a selected inspecting location along a radiation path, comprising:

a source of radiation for directing a beam of radiation in a first direction along the radiation path;

scanning area selecting means, interposed in the radiation path between the radiation source and the selected inspecting location, for sequentially selecting area portions of the beam of radiation and for transmitting the selected area portions to preselected area portions of the inspecting location;

scanning-area determining means, responsive to said scanning area selecting means, for determining the area portions of the inspecting location selected by the scanning-area selecting means;

an illuminator, disposed in the radiation path of the generated radiation, beyond the selected inspecting location, activated in response to the reception of radiation passing through the object disposed at the selected location, for backscattering the received radiation and providing a source of fluorescence in a second direction along the radiation path, opposite the first direction, through the object at the selected location,

detection means, disposed in the radiation path between the selected inspecting location and the radiation source, operative to receive first backscattered and fluorescent radiation traveling in the second direction from the illuminator through the object at the inspecting location, and operative to receive second backscattered and fluorescent radiation interacting with the object at the inspecting location, the detection means generating signals responsive to the received first and second backscattered and fluorescent radiation, and including a data processing means responsive to the scanning-area determining means for processing the response signals corresponding to the first and second backscattered and fluorescent radiation to obtain a radiographic representation of the object.

2. The system according to claim 1, wherein the detection means further includes display means, responsive to the data processing means, for generating an image of the object according to the radiographic representation of the object.

3. The system according to claim 1, wherein the detection means further includes a signal conditioning means, responsive to the detecting means for conditioning the response signals, and wherein the data processing means is responsive to the signal conditioning means for processing the signals generated by the signal conditioning means.

4. The system according to claim 2, wherein the detection means further comprises an image memory, responsive to the data processing means for storing the signals processed by the data processing means, said display means being responsive to the signals stored by the image memory to generate the radiographic image of the object.

5. The system according to claim 1, wherein said illuminating means comprises a solid material having a low atomic number.

6. The system according to claim 1, wherein the illuminator comprises a solid material having a high atomic number.

7. A system for radiographically inspecting an object disposed at a selected inspecting location along a radiation path, comprising:

a source of radiation for directing a beam of radiation in a first direction along the radiation path;

scanning area selecting means, interposed in the radiation path between the radiation source and the selected inspecting location, for sequentially selecting area portions of the beam of radiation and for transmitting the selected area portions to preselected area portions of the inspecting location;

scanning-area determining means, responsive to said scanning area selecting means, for determining the area portions of the inspecting location selected by the scanning-area selecting means;

an illuminator, disposed in the radiation path of the generated radiation, beyond the selected inspecting location, activated in response to the reception of radiation passing through the object disposed at the selected location, for backscattering the received radiation and providing a source of fluorescence in a second direction along the radiation path, opposite the first direction, through the object at the selected location, said illuminator comprising

liquid-retaining means positioned adjacent the selected inspecting location and the object, and

a liquid having a low atomic number, disposed within the liquid retaining means; and

detection means, disposed in the radiation path between the selected inspecting location and the radiation source, operative to receive first backscattered and fluorescent radiation traveling in the second direction from the illuminator through the object at the inspecting location, and operative to receive second backscattered and fluorescent radiation interacting with the object at the inspecting location, the detection means generating signals responsive to the received first and second backscattered and fluorescent radiation, and including a data processing means responsive to the scanning-area determining means for processing the response signals corresponding to the first and second backscattered and fluorescent radiation to obtain a radiographic representation of the object.

8. A system for radiographically inspecting an object disposed at a selected inspecting location along a radiation path, comprising:

a source or radiation for directing a beam of radiation in a first direction along the radiation path;

scanning area selecting means, interposed in the radiation path between the radiation source and the selected inspecting location, for sequentially selecting area portions of the beam of radiation and for transmitting the selected area portions to preselected area portions of the inspecting location;

scanning-area determining means, responsive to said scanning area selecting means, for determining the area portions of the inspecting location selected by the scanning-area selecting means;

an illuminator, disposed in the radiation path of the generated radiation, beyond the selected inspecting location, activated in response to the reception of radiation passing through the object disposed at the selected location, for backscattering the received radiation and providing a source of fluorescence in a second direction along the radiation path, opposite the first direction, through the object at the selected location, said illuminator comprising

liquid-retaining means positioned adjacent the selected inspecting location and the object, and

a liquid having a high atomic number, disposed within the liquid retaining means; and

detection means, disposed in the radiation path between the selected inspecting location and the radiation source, operative to receive first backscattered and fluorescent radiation traveling in the second direction from the illuminator through the object at the inspecting location, and operative to receive second backscattered and fluorescent radiation interacting with the object at the inspecting location, the detection means generating signals responsive to the received first and second backscattered and fluorescent radiation, and including a data processing means responsive to the scanning-area determining means for processing the response signals corresponding to the first and second backscattered and fluorescent radiation to obtain a radiographic representation of the object.

9. A system for radiographically inspecting an object having a plurality of sections disposed at a selected inspecting location along a radiation path, comprising:

a source of radiation for directing a beam of radiation in a first direction along the radiation path;

scanning area selecting means, interposed in the radiation path between the radiation source and the selected inspecting location, for sequentially selecting area portions of the beam of radiation and for transmitting the selected area portions to preselected area portions of the inspecting location;

scanning-area determining means, responsive to said scanning area selecting means, for determining the area portions of the inspecting location selected by the scanning-area selecting means;

an illuminator comprising a plurality of sections each having liquid retaining means, each of said liquid-retaining means being positioned immediately beyond a successive one of the plurality of sections of the object at the selected inspecting location, and a liquid, disposed within one of the liquid retaining means, said illuminator being activated in response to the reception of radiation passing through the object disposed at the selected location, for backscattering the received radiation and providing a source of fluorescence in a second direction along the radiation path, opposite the first direction, through the object at the selected location; and

detection means, disposed in the radiation path between the selected inspecting location and the radiation source, operative to receive first backscattered and fluorescent radiation traveling in the second direction from the illuminator through the object at the inspecting location, and operative to receive second backscattered and fluorescent radiation interacting with the object at the inspecting location, the detection means generating signals responsive to the received first and second backscattered and fluorescent radiation, and including a data processing means responsive to the scanning-area determining means for processing the response signals corresponding to the first and second backscattered and fluorescent radiation to obtain a radiographic representation of the sections of the object located between the radiation source and the illuminator.

10. The system according to claim 9, wherein the data processing means includes means for subtracting a first representation obtained for sections of the object disposed between the radiation source and a desired section of the object, not including the desired section, and a next representation obtained for sections of the object disposed between the radiation and the desired section, including the desired section, to obtain a representation of the desired section of the object.

11. A system for radiographically inspecting an object having a plurality of sections disposed at a selected inspecting location along a radiation path, comprising:

a source of radiation for directing a beam of radiation in a first direction along the radiation path;

scanning area selecting means, interposed in the radiation path between the radiation source and the selected inspecting location, for sequentially selecting area portions of the beam of radiation and for transmitting the selected area portions to preselected area portions of the inspecting location;

scanning-area determining means, responsive to said scanning area selecting means, for determining the area portions of the inspecting location selected by the scanning-area selecting means;

an illuminator having a plurality of sections each comprising a a high atomic number element uniformly interspersed in a bonding material, each of the plurality of sections of the illuminator being distributed at a junction between successive sections of the object at the selected inspecting location, said illuminator being activated in response to the reception of radiation passing through the object disposed at the selected location, for backscattering the received radiation and providing a source of fluorescence in a second direction along the radiation path, opposite the first direction, through the object at the selected location; and

detection means, disposed in the radiation path between the selected inspecting location and the relative source, operative to receive first backscattered and fluorescent radiation traveling in the second direction from the illuminator through the object at the inspecting location, and operative to receive second backscattered and fluorescent radiation interacting with the object at the inspecting location, the detection means generating signals responsive to the received first and second backscattered and fluorescent radiation, and including a data processing means responsive to the scanning-area determining means for processing the response signals corresponding to the first and second backscattered and fluorescent radiation to obtain a radiographic representation of the distribution of the bonding material between the successive section of the object.

12. The system according to claim 11, wherein each of the plurality of sections of the illuminator comprises a unique high atomic number element, and wherein intensity and energy levels for the radiation from the radiation source is varied to determine the distribution of the bonding material between certain successive sections of the object in accordance with the atomic number of the unique high atomic number element of the section of the illuminator having the bonding material and distributed between the certain successive sections.

13. A method for radiographically inspecting an object disposed at a selected inspecting location along a radiation path, comprising the steps of:

transmitting a radiation beam along a radiation path in a first direction toward the selected inspecting location;

sequentially selecting area portions of the beam of radiation and transmitting the selected area portions to preselected area portions of the inspecting location;

determining the area portions of the inspecting location to which the sequentially selected area portions of the beam of radiation are being transmitted;

backscattering radiation passing along the radiation path in the first direction and through an object at the inspecting location, in a second direction along the radiation path, opposite the first direction, through the object at the selected location;

detecting radiation traveling through an object at the inspecting location and backscattered in the second direction and detecting radiation interacting with the object and backscattered in the second direction;

generating signals in response to the detected radiation; and

processing the response signals for the sequentially selected area portions of the inspecting location to obtain a radiographic representation of the object at the inspecting location.

14. The method according to claim 13, wherein the step of processing includes the substep of generating an image of the object according to the radiographic representation of the object.

15. The method according to claim 13, wherein the step of processing includes the substep of storing the response signals to generate an image of the object.

16. A method for radiographically inspecting an object disposed at a selected inspecting location along a radiation path, the object including a plurality of sucessive sections with bonding material distributed between the successive sections for bonding the successive sections of the object, the method comprising the steps of:

transmitting a radiation beam along a radiation path in a first direction toward the selected inspecting location;

sequentially selecting area portions of the beam of radiation and transmitting the selected area portions to preselected area portions of the inspecting location;

determining the area portions of the inspecting location to which the sequentially selected area portions of the beam of radiation are being transmitted;

backscattering radiation passing along the radiation path in the first direction and through an object at the inspecting location, in a second direction along the radiation path, opposite the first direction, through the object at the selected inspecting location;

detecting first radiation traveling through an object at the inspecting location and backscattered in the second direction and detecting second radiation interacting with the object and backscattered in the second direction;

generating signals in response to the detected first and second radiation; and

processing the response signals for the sequentially selected area portions of the inspecting location to obtain a radiographic representation of the distribution of the bonding material between the successive sections of the object.