A rotating modulation imager for locating mid-range point sources

Kowash, Benjamin R.; Wehe, D.K.; Fessler, Jeffrey A.

doi:10.1016/j.nima.2008.12.233

Cited by 31 publications

(23 citation statements)

References 8 publications

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“…Thus the rotation causes the transmission of the grid viewing a gamma-ray Corresponding author, E-mail: jhha@kaeri.re.kr c Atomic Energy Society of Japan source that was a modulated count-rates; the modulation pattern depends on the location of the source in the FOV. The image resolution (Δθ ) and FOV for the gamma-ray imaging system are defined as 3) :…”

Section: Principle Of Image Reconstructionmentioning

confidence: 99%

“…The gammaray imaging system using RMCs has been studied for astronomical, medical application, and homeland security. [1][2][3][4] The greatest advantage of the RMC imager is that this system does not requires a position-sensitive detector so as to find the location of the gamma-ray source and their ability to achieve good image resolution over a relatively wide field-of-view (FOV). 3) Therefore this feature allows for significant amount of flexibility not only detector selection but also the geometry of the system.…”

Section: Introductionmentioning

confidence: 99%

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Gamma-ray Imaging System with a Rotation Collimator

Kim

2011

Progress in Nuclear Science and Technology

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The performance of a gamma-ray imaging system consisting of a gridded collimator and coaxial NaI(Tl) detector was investigated. A gamma-ray imaging system with rotation collimators does not require a position-sensitive detector so as to find the location of gamma-ray sources and therefore this feature allows for significant amount of flexibility not only detector selection but also the geometry of the system. A reconstructed image from the 137 Cs gamma-ray source have been obtained by using the simple flat-fielded back-projection algorithm. The background events are jumbled together in the correct modulation-patterns. Therefore a possibility may be caused by those events that the image is reconstructed at random on the image plane. The theoretical image resolution for the current proof-of-principle gamma-ray imager is ∼ 1 o with a FOV ∼ 53.6 o . The image resolution with FWHM shows about 11.2 o . Therefore our gamma-ray imaging system is required the more collimators, because the reconstructed image was significantly affected by the modulation patterns. Future research will be to focus on the improvement of the image resolution with two or more collimators.

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Section: Principle Of Image Reconstructionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gamma-ray Imaging System with a Rotation Collimator

Kim

2011

Progress in Nuclear Science and Technology

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“…In this experiment, a Maximum Likelihood Estimation Maximization (MLEM) algorithm is used to reconstruct the source location from the transmission function. A Bootstrap re-sampling T 2009 IEEE Nuclear Science Symposium Conference Record N20-7 9781-4244-3962-1/09/$25.00 ©2009 IEEE method, as described by Kowash [6], is used to determine the uncertainty of the image reconstruction.…”

Section: Basics Of Rmc Imagingmentioning

confidence: 99%

“…Sharma proposed to use the RMC in the medical field (NSECT) [5]. Kowash proposed to use the RMC in the orphan source search problem [6]. With the performance characteristics of RMCs it is desirable to determine if it is feasible to locate neutron sources with the use of an RMC.…”

Section: Introductionmentioning

confidence: 99%

Thermal neutron imaging with a Rotationally Modulated Collimator (RMC)

Boyce

Kowash

Wehe

2009

2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)

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The Rotating Modulation Collimator has been modified to image thermal neutron sources. The components of the RMC imaging system were modified to suit thermal neutrons. The experiment compared two detectors (He3 and BF3) and two mask materials (cadmium and borated epoxy) for a 77mCi PuBe source. Preliminary results indicate that both He3 and BF3 detectors may be used with the RMC. Further efforts will be made to reduce the uncertainty in the system.

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“…Far-field RMC imaging is commonly employed in applications of astronomy (Smith et al, 2004). Nearfield RMC imaging, on the other hand, is noticeably growing for medical, environmental and military applications (Sharma et al, 2008;Kowash et al, 2009;Kowash and Wehe, 2011).…”

Section: Introductionmentioning

confidence: 99%

Using a gas-filled detector in a rotation modulation collimator system for near-field imaging

Alrefae¹

2012

Int. J. Phys. Sci.

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Rotation modulation collimators (RMC) are a class of nuclear imaging devices that are found in various applications. RMC are used for far-field applications, as in astronomy, and in near-field applications, as in environmental, medical and military uses. The typical detectors used in RMC system are scintillators and semiconductors , which detect γ radiation only. This work investigates the utilization of gas-filled detectors, which detect  particles as well as γ rays. Hence, a simple RMC system is built that utilizes a Geiger-Muller (GM) tube as a detector. To help assess the new system, a direct image construction algorithm is developed. Results of the assessment show that the newly built system is well capable of imaging radiation sources in the near-field.

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A rotating modulation imager for locating mid-range point sources

Cited by 31 publications

References 8 publications

Gamma-ray Imaging System with a Rotation Collimator

Gamma-ray Imaging System with a Rotation Collimator

Thermal neutron imaging with a Rotationally Modulated Collimator (RMC)

Using a gas-filled detector in a rotation modulation collimator system for near-field imaging

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