A New Type of Combined Neutron/X-ray Digital Imaging System for Explosive Detection and Homeland Security Applications

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Jonah Morgan
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1 A New Type of Combined Neutron/X-ray Digital Imaging System for Explosive Detection and Homeland Security Applications Presented By: Vaibhav Sinha PhD Candidate Department of Nuclear Engineering Missouri University of Science and Technology

2 Motivation A. Different attenuation behaviors of neutron and x-ray produces different radiographic images with different characteristics. For example, boron strongly attenuate neutron but not x-ray B. How about fusing two different images (one using neutron and the other x-ray) of the same object? C. We may be able to extract more information from the fused images. D. How about visualizing the structure and composition of interested objects 3D using this technique?

3 X-Ray Cross Section H D C O Al Si Fe Neutron Cross Section Attenuation Behavior

4 Interaction of (a) neutron and (b) X-ray with an atom.

5 Fusion of neutron and x-ray images (simulated) (a) (a) (b) (b) (c) X-Ray Image Neutron Image Fusion Beryllium Europium Boron Beryllium Europium Boron Beryllium Europium Boron Simulation Assumption: The mono-energetic x-ray energy (50 kev) Thermal neutron energy ( ev)

6 Fusion of neutron and x-ray images (simulated) Borosilicate glasses with different boron concentration X-ray Neutron Fused

7 Past Research A. NDE methods have been applied individually (Neutron or X- ray) for research. B. Failures to obtain comprehensive analysis. C. If applied together, separate experimental set-up were used for neutron and x-ray imaging. D. Such system, difficult to calibrate, prone to measurement inaccuracies and doesn t allow for instant evaluation of imaging objects

8 Objective A.We propose to develop and demonstrate successful operation of a neutron/x-ray combined computed tomography (NXCT) system. B.This is the first approach to develop a neutron and x-ray combined computed tomography system.

9 Radiation Sources Parameter Value Flux at Port Value at 200 kw kv Range ma Range 0 30 Focal Spot 0.4 x1 mm 2 Thermal Neutron Flux Epithermal Neutron Flux ~10 8 n/cm 2 s ~10 6 n/cm 2 s

10 (a) Schematic of MSTR NXCT Facility (b) Photograph of MSTR Neutron Beam Path

11 Neutron Beam Path and Beam Port (Adopted from Bill Bonzer and Christopher M. Caroll, Safety Analysis Report for MSTR, 2008)

12 Isometric view of the NXCT Facility MSTR NXCT neutrons

13 MSTR Full Power Neutron Flux Spectrum (from Kulage Z.A., Mueller G.E., Usman S. and Kumar A., Characterization of Neutron Flux Spectrum at MSTR, M.S. Thesis, 2010)

14 X-Ray Spectrum Generated by Spekcalc Software

15 Sensor Description Scintillator + CMOS X-Ray Image Sensor Parameters Value Pixel Pitch 48 µm Dynamic Range Frame rate Field of View 4000:1 2.7 FPS 5 cm x 5 cm MCP Based Neutron Image Sensor Parameters Value Pixel Pitch 50 µm Dynamic Range 10 7 Sensitivity 0.1 c/cm 2 s Field of View Ф 2.5 cm

16 Selection of MCP Based Neutron Image Sensor A. The imaging object can be placed directly next to the detector window compared to the optical camera based system where a mirror and a lens are needed to capture an image. B. Replacement of the optical camera readout with the delay line anode helps to increase the sensitivity of the imaging system. C. Therefore the MCP based detector with the delay line anode is also better in terms of image acquisition time and overall ease of operation for tomography applications.

17 Neutron Image Sensor Description

18 Scintillator+CMOS X-Ray Image Sensor

19 Stages and Motion Control Equipments

20 Stages and Lab Jack Physical Properties Physical Parameter Micro step Size Resolution Speed Resolution Linear Stage Rotary Stage μm deg worm gear ratio X Y Stage mm/s 13.2 deg/s Up to 29 mm/s Z Axis Stage μm 0.40 mm 1.0 mm/s (Small Load) 0.5 mm/s (Maximum Load) Accuracy +/ 15 μm +/ 0.05 deg +/ 21 μm 5% Step acc. Travel Distance Load Capacity 300 mm 360 deg rotation mm 50 mm 200 N cm (Maximum Cantilever Load) 20 kg 10 kg 15 kg

21 Design of NXCT System (left) and Developed Experimental Set-up (Right)

25 Imaging setup in the basement of MSTR Operating room on the 2 nd floor of MSTR

26 Radiation Safety Audio/visual alarms in conjunction with the entrance door disconnect switch provide foolproof radiation safety for each experiment. These devices assure compliance with FDA CDRH safety requirements for radiation producing devices

27 System Control

28 GUI for NXCT Component Control

29 Neutron Sensor Image Display

30 Image Acquisition (x-ray) Memory Flash drive Wooden Pencil Borax in Plastic Vial Borosilicate Testtube

31 Image Acquisition (x-ray) Different Views of Rock Sample to Investigate Water Diffusion

32 Image Acquisition (x-ray) Simulated Phantom as a TRISO substitute

33 Image Acquisition (neutron & x-ray) (a) (b) Neutron (Left) and X-Ray (Right) Image of Borax in Vial

34 Image Acquisition (neutron & x-ray) (a) (b) Neutron (Left) and X-Ray (Right) Image of Memory Flash Card

37 Image Acquisition (neutron & x-ray) (a) (b) (c) Neutron X-ray Fused Neutron (Left) and X-Ray (Right) Image of Mechanical Pencil

38 Potential Applications of the Facility Mechanical testing of structural materials. Non-destructive evaluation of TRISO nuclear fuel particles. Particle tracking in complex flows using fluoroscopy techniques. Non-destructive evaluation of biomaterials such as artificial bones. Homeland-security applications.

39 Conclusion The construction and implementation of the NXCT imaging system at Missouri S&T is the first such method to be developed. This system will provide for great benefits across multiple disciplines and particularly in nondestructive evaluation. The concept of NXCT can be useful for concealed material detection, material characterization, investigation of complex geometries involving different atomic number materials and real time imaging for in-situ studies.

40 Neutron imaging has the ability to detect light atomic number materials, including typical explosive materials. One immediately obvious application would be during the scanning of airport baggage, especially lead-covered items that conceal plastic weapons or explosive materials. It has been shown that fusion of neutron and x-ray images provides for greater image clarity and usefulness. The many uses of NXCT system are still being determined and would allow for improved research in practically all engineering disciplines.

41 Acknowledgement Missouri S&T Nuclear Engineering Faculty: Dr. A. Kumar, Dr. G. Mueller, Dr. S. Usman, Dr. C. Castano, Dr. Ayodeji, Dr. X. Liu Advanced Radiation Computed Tomography Laboratory (ARTLAB) Research Group Reactor Staff: Bill Bonzer, Craig Reisner, Raymond Kendrick, Maureen Henry DOE General Infrastructure Support and partial support from CBTRR Missouri S&T

42 Thank you! QUESTIONS?

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