Pixelated gamma detector

Patent metadata

Field	Value
Publication number	US-9529097-B1
Application number	US-201615198502-A
Country	US
Kind code	B1
Filing date	Jun 30, 2016
Priority date	Jun 30, 2016
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A pixelated gamma detector includes a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis, a collimator assembly having longitudinal walls separated by collimator septum, the collimator septum spaced apart to form collimator channels, the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum, and a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly. A system and a method for inspecting and/or detecting defects in an interior of an object are also disclosed.

First claim

We claim:

1. A pixelated gamma detector comprising:
a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis of the scintillator column;
a collimator assembly having about parallel longitudinal walls, the longitudinal walls separated by about parallel collimator septum, the collimator septum spaced apart to form a plurality of collimator channels;
respective ones of the scintillator crystals having a first height and width about equal in dimension to a corresponding dimension of the collimator channel;
respective ones of the optical transparent element having a second height and width about equal in dimension to a corresponding dimension of the collimator septum;
the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, and the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum; and
a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly.

2. The pixelated gamma detector of claim 1 , including the respective optical transparent elements formed from at least one of glass, acrylic, optical epoxy, and a gas.

3. The pixelated gamma detector of claim 1 , including the respective scintillator crystals formed from at least one of sodium iodide: thallium, lutetium oxy-orthosilicate, lutetium yttrium oxy-orthosilicate, bismuth germanium oxide, cerium bromide, lanthanum bromide, and gadolinium pyrosilicate.

4. The pixelated gamma detector of claim 1 , including the scintillator column assembly encased in an optical transparent casing.

5. The pixelated gamma detector of claim 4 , the optical transparent casing formed from at least one of clear quartz, glass, optically transparent epoxy, optical liquid, and a gas.

6. The pixelated gamma detector of claim 1 , including one or more of the respective transparent elements having a different directional optical reflectivity property.

7. An inspection system for inspection of an object interior, the system comprising:
a radiation source, a radiation shield, and a pixelated gamma detector;
a control processor connected to an electronic communication network, the control processor in communication with the radiation source and the pixelated gamma detector across the electronic communication network;
the radiation source, the radiation shield, and the pixelated gamma detector configured to be inserted into the object interior, and configured to be translated along a longitudinal axis of the object;
the radiation source configured to emit gamma rays or x-rays, the shield located in proximity to the radiation source and configured to absorb a portion of direct radiation; and
the pixelated gamma detector configured to receive backscatter radiation off the object interior, the pixelated gamma detector including:
a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis of the scintillator column;
a collimator assembly having about parallel longitudinal walls, the longitudinal walls separated by about parallel collimator septum, the collimator septum spaced apart to form a plurality of collimator channels;
respective ones of the scintillator crystals having a first height and width about equal in dimension to a corresponding dimension of the collimator channel;
respective ones of the optical transparent element having a second height and width about equal in dimension to a corresponding dimension of the collimator septum;
the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, and the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum;
a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly; and
the scintillator column assembly encased in an optical transparent casing.

8. The system of claim 7 , including:
a first signal output from the first photosensor and a second signal output from the second photosensor;
the first and the second signal outputs connected to a respective signal splitter, each respective signal splitter configured to provide an output signal to a gate circuit and to a readout circuit.

9. The system of claim 8 , including the gate circuit configured to provide a gate signal to the readout circuit.

10. The system of claim 8 , the readout circuit including an analog-to-digital convertor configured to digitize each respective output signal of the splitter.

11. The system of claim 9 , the readout circuit including an analog-to-digital convertor configured to digitize each respective output signal of the splitter, the digitization of each respective output signal occurring under control by the gate signal.

12. The system of claim 8 , the readout circuit including an output controller configured to compare the respective digitized output signals to determine the relative position x of radiation event.

13. The system of claim 7 , including a workstation configured to:
analyze data of relative position x of radiation events provided by the readout circuitry, and backscatter radiation based on the relative position x; and
display data representative of defects in the object interior.

14. A method for inspection of an object interior, the method comprising:
inserting a radiation source, a radiation shield, and a pixelated gamma detector into the object interior, the radiation source emitting gamma rays or x-rays, the shield located in proximity to the radiation source and absorbing a portion of direct radiation;
translating the radiation source, the radiation shield, and the pixelated gamma detector along a longitudinal axis of the object;
the pixelated gamma detector receiving backscatter radiation off the object interior, the pixelated gamma detector including:
a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis of the scintillator column;
a collimator assembly having about parallel longitudinal walls, the longitudinal walls separated by about parallel collimator septum, the collimator septum spaced apart to form a plurality of collimator channels;
respective ones of the scintillator crystals having a first height and width about equal in dimension to a corresponding dimension of the collimator channel;
respective ones of the optical transparent element having a second height and width about equal in dimension to a corresponding dimension of the collimator septum;
the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, and the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum;
a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly; and
the scintillator column assembly encased in an optical transparent casing.

15. The method of claim 14 , including:
the first photosensor providing a first signa

Assignees

• Gen Electric

Inventors

• Dolinsky Sergei Ivanovich
• Yanoff Brian David
• Guida Renato
• Ivan Adrian

Classifications

• G01N2223/053

  back scatter · CPC title

• G01T1/202 Primary

  the detector being a crystal · CPC title

• G01N2223/646

  flaws, defects · CPC title

• G01T1/2002

  Optical details, e.g. reflecting or diffusing layers · CPC title

• G01T1/1644

  using an array of optically separate scintillation elements permitting direct location of scintillations (G01T1/1645 takes precedence) · CPC title