Gamma-ray Imaging Methods

Vetter, K.; Mihailescu, Lucian; Nelson, K.; Valentine, J.D.; Wright, D.

doi:10.2172/1036848

Cited by 6 publications

(4 citation statements)

References 42 publications

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“…Because of the mask's cyclic nature, the binary number can be written as a vector containing the integer number of zeros bounded on either end by ones. For example, the number 0 1 1 would be shifted to 1 0 1 and could be written as the vector [1]. Also, the number [0 1 0 1 0 1 0 0] can be shifted to [1 0 1 0 1 0 0 0], and the corresponding vector is [1 1 3].…”

Section: Appendix Binary Approach Proofmentioning

confidence: 99%

“…Collimator and coded aperture systems use intervening material or a mask to create a unique detection pattern, which can be used to identify the source's direction. However, the intervening material reduces the detector's field-of-view (FOV) [1], which increases the time required to survey surrounding areas. For higher gamma energy levels, the system's weight and portability can become problematic as shown by the 32,000 lb SuperMISTI system [2] and 2700 lb Large-Area Imager [3].…”

Section: Introductionmentioning

confidence: 99%

“…These systems are mounted on mobile platforms in order to image the area of interest. Complicate Compton Cameras can offer up to a 4 FOV [4] and can distinguish between background and source radiation [1,5]. However, these systems require multiple detectors to measure coincident Compton events and usually ignore full-energy-peak (FEP) information.…”

Section: Introductionmentioning

confidence: 99%

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Rotating scatter mask optimization for gamma source direction identification

Holland

Bevins

Burggraf

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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Rotating scattering masks have shown promise as an inexpensive, lightweight method with a large field-of-view for identifying the direction of a gamma emitting source or sources. However, further examination of the current rotating scattering mask design shows that changing the geometry may improve the identification by reducing or eliminating degenerate solutions and lower required count times. These changes should produce more linearly independent characteristics for the mask, resulting in a decrease in the mis-identification probability. Three approaches are introduced to generate alternative mask geometries. The eigenvector method uses a spring-mass system to create a geometry basis. The binary approach uses ones and zeros to represent the geometry with many possible combinations allowing for additional design flexibility. Finally, a Hadamard matrix is modified to examine a decoupled geometric solution. Four criteria are proposed for evaluating these methodologies. An analysis of the resulting detector response matrices demonstrates that these methodologies produced masks with superior identification characteristics than the original design. The eigenvector approach produces the least linearly dependent results, but exhibits a decrease in average efficiency. The binary results are more linearly dependent than the eigenvector approach, but this design achieves a higher average efficiency than original. The Hadamard-based method produced a lower maximum, but a higher average linear dependence than the original design. Further possible design enhancements are discussed.

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Section: Appendix Binary Approach Proofmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rotating scatter mask optimization for gamma source direction identification

Holland

Bevins

Burggraf

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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“…To support NER operations, CHIS is conducting a large-scale scientific research program. Developing and characterizing high-sensitivity directional and imaging gamma-ray measurement equipment is one of the program's main areas of interest [11,[14][15][16][17][18]. NER research includes the development of gamma detectors featuring Compton imaging [19,20].…”

Section: Motivation Of the Researchmentioning

confidence: 99%

Demonstration of a Cruciform Gamma-Ray Direction-Finder with both Self-Shielding and Compton Imaging Modes

Cevik

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Effective technologies for locating radioactive materials across large areas are being developed as governments globally prepare for nuclear incidents. The present study investigates a Cruciform device that provides both Compton gamma imaging and simple direction-finding based on self shielding. The Compton imaging and selfshielding modes perform well for detecting a single medium-energy source at multiple azimuthal angles. The performance degrades, however, for both modes at higher elevation angles.The self-shielding mode can determine the source direction even for low-energy sources when the Compton-scattering mode is impossible. The Compton-scattering mode on the other hand provides gamma images of two equal-energy sources, where the self-shielding mode points to the source distribution centroid.In conclusion, the Cruciform detector helps determine distant sources, especially near the horizon. The Compton mode provides actual imaging capabilities in the presence of higher energy sources, while its self-shielding mode helps determine lowenergy sources.

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