nuclear resonance fluorescence
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2021 ◽  
Vol 11 (24) ◽  
pp. 11866
Author(s):  
Khaled Ali ◽  
Heishun Zen ◽  
Hideaki Ohgaki ◽  
Toshiteru Kii ◽  
Takehito Hayakawa ◽  
...  

One of the most noteworthy aspects of computed tomography (CT) based on the nuclear resonance fluorescence (NRF) transmission method is the isotope selectivity that makes it possible to discern an isotope of interest from other isotopes within a sample. We experimentally obtained a three-dimensional (3D) isotope-selective CT image based on the NRF transmission method (3D NRF-CT) for the enriched lead isotope distribution of 208Pb in a cylindrical holder in a previous study. The cylindrical holder’s diameter and height are 25 mm and 20 mm, respectively. The NRF-CT imaging technique requires a considerable data accumulation time. It took 48 h to obtain an image with a resolution of 4 mm/pixel in the horizontal plane and 8 mm/pixel in the vertical plane using a laser Compton scattering (LCS) gamma-ray beam with a beam size of 2 mm and a flux density of 10 photons/s/eV. Improving the NRF-CT image resolution with the existing hardware is challenging. Therefore, we proposed an alternative method to improve the NRF-CT image resolution using the fusion visualization (FV) technique by combining the NRF-CT image including isotopic information with a gamma-CT image, which provides better pixel resolution. The 3D gamma-CT image for the same sample was measured at the same beamline BL1U in the ultraviolet synchrotron orbital radiation-III (UVSOR-III) synchrotron radiation facility at the Institute of Molecular Science at the National Institutes of Natural Sciences in Japan under similar experimental conditions except for the LCS gamma-ray beam flux and beam size. Obtaining a 3D gamma-CT image with a resolution of 1 mm/pixel took 5 h using an LCS gamma-ray beam with a beam size of 1 mm and a flux density of 0.7 photons/s/eV. The data processing of the FV technique has been developed, and the 3D NRF-CT image quality was improved.


2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Miroslav Pardy ◽  

We will consider the string, the left end of which is fixed at the beginning of the coordinate system, the right end is fixed at point l and mass m is fixed between the ends of the string. We determine the vibration of such system. The proposed model can be also related in the modified form to the problem of the Mossbauer effect, or recoil less nuclear resonance fluorescence, which is the resonant and recoil-free emission and absorption of gamma radiation by atomic nuclei bound in a solid.(Mossbauer,1958)


2021 ◽  
Vol 11 (8) ◽  
pp. 3415
Author(s):  
Khaled Ali ◽  
Heishun Zen ◽  
Hideaki Ohgaki ◽  
Toshiteru Kii ◽  
Takehito Hayakawa ◽  
...  

Combining the nuclear resonance fluorescence (NRF) transmission method with computed tomography (CT) can be a novel method for imaging the isotope distributions, which is indispensable in nuclear engineering. We performed an experiment to reconstruct a three-dimensional NRF-CT image with isotope selectivity of enriched lead isotope rods (208Pb) together with a set of different rods, including another enriched isotope (206Pb), iron, and aluminum rods, inserted into a cylindrical aluminum holder. Using a laser Compton scattering (LCS) gamma ray beam with a 5.528 MeV maximum energy, 2 mm beam size, and 10 photon·s−1·eV−1 flux density, which is available at the BL1U beamline in the ultraviolet synchrotron orbital radiation-III (UVSOR-III) synchrotron radiation facility at the Institute of Molecular Science at the National Institutes of Natural Sciences in Japan, and we excited the Jπ = 1− NRF level at 5.512 MeV in 208Pb. An isotope-selective three-dimensional NRF-CT image of the 208Pb isotope distribution was experimentally obtained for the first time with a pixel resolution of 4 mm in the horizontal plane.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haoyang Lan ◽  
Tan Song ◽  
Xingde Huang ◽  
Shengqiang Zhao ◽  
Jianliang Zhou ◽  
...  

AbstractThere is an increasing challenge to prevent illicit drug smuggling across borders and seaports. However, the existing techniques in-and-of-themselves are not sufficient to identify the illicit drugs rapidly and accurately. In the present study, combining nuclear resonance fluorescence (NRF) spectroscopy and the element (or isotope) ratio approach, we present a novel inspection method that can simultaneously reveal the elemental (or isotopic) composition of the illicit drugs, such as widely abused methamphetamine, cocaine, heroin, ketamine and morphine. In the NRF spectroscopy, the nuclei are excited by the induced photon beam, and measurement of the characteristic energies of the emitted $$\gamma $$ γ rays from the distinct energy levels in the excited nuclei provides “fingerprints” of the interested elements in the illicit drugs. The element ratio approach is further used to identify drug elemental composition in principle. Monte Carlo simulations show that four NRF peaks from the nuclei $$^{12}$$ 12 C, $$^{14}$$ 14 N and $$^{16}$$ 16 O can be detected with high significance of 7−24$$\sigma $$ σ using an induced photon beam flux of $$10^{11}$$ 10 11 . The ratio of $$^{14}N$$ 14 N /$$^{12}C$$ 12 C and/or $$^{16}O$$ 16 O /$$^{12}C$$ 12 C for illicit drugs inspected are then extracted using the element ratio approach. It is found that the present results of simulations are in good agreement with the theoretical calculations. The feasibility to detect the illicit drugs, inside the 15-mm-thick iron shielding, or surrounded by thin benign materials, is also discussed. It is indicated that, using the state-of-the-art $$\gamma $$ γ -ray source of high intensity and energy-tunability, the proposed method has a great potential for identifying drugs and explosives in a realistic measurement time.


2020 ◽  
Vol 67 (8) ◽  
pp. 1976-1984
Author(s):  
Khaled Ali ◽  
Hideaki Ohgaki ◽  
Heishun Zen ◽  
Toshiteru Kii ◽  
Takehito Hayakawa ◽  
...  

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