High-accuracy Geant4 simulation and semi-analytical modeling of nuclear resonance fluorescence

Vavrek, Jayson R.; Henderson, Brian S.

doi:10.1016/j.nimb.2018.07.023

Cited by 7 publications

(1 citation statement)

References 21 publications

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“…For example, Jordan and Warren [7] and Hayakawa et al [8] developed a Monte Carlo simulation for the NRF process. More recently, Vavrek et al [9,10] have upgraded the simulation model of Jordan and Warren to enhance its accuracy. They have tested the simulation model, which lowered the discrepancy between the simulation and experiment to approximately 15%.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of γ − γ Correlation Functions

Omer

Bakr

2020

Atoms

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γ − γ correlation functions are mathematical expressions that describe the angular distribution of cascade γ -rays emitted from an atomic nucleus. Cascade transitions may occur in either a two-step deexcitation or through an excitation-deexcitation process of a particular energy level inside the nucleus. In both cases, the nucleus returns to its ground energy state. Spin and parity of the excited state can be determined experimentally using the asymmetry of the angular distribution of the emitted radiation. γ − γ correlation functions are only valid for point-like targets and detectors. In the real experiments, however, neither the target nor the detector is point-like. Thus, misassignment of the spin-parity of energy levels may easily take place if only the analytical equations are considered. Here, we develop a new Monte Carlo simulation method of the γ − γ correlation functions to account for the extended target and detector involved in spin-parity measurements using nuclear resonance fluorescence of nuclei. The proposed simulation tool can handle arbitrary geometries and spin sequences. Additionally, we provide numerical calculations of a parametric study on the influence of the detection geometry on the angular distribution of the emitted γ -rays. Finally, we benchmark our simulation by comparing the simulation-estimated asymmetry ratios with those measured experimentally. The present simulation can be employed as a kernel of an implementation that simulates the nuclear resonance fluorescence process.

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Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of γ − γ Correlation Functions

Omer

Bakr

2020

Atoms

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Monte Carlo Simulation and Analysis of Specified Element Samples by Nuclear Resonance Fluorescence Detection

Zhang

Zheng

Wang

et al. 2023

Springer Proceedings in Physics

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The detection of explosives and drugs in large cargo distribution centers such as customs and logistics stations has a great effect on preventing smuggling crimes and terrorist incidents. However, the relatively thick shielding of container cargo makes the material composition information obtained by conventional detection methods such as X-ray transmission detection and imaging technology very limited. Nuclear Resonance Fluorescence (NRF) is an emerging nondestructive assay technology that uses the specific resonance energy of nuclides to identify unknown nuclides, which can be used to detect and analyze the isotopic composition of the inspected cargo. In this paper, according to the theoretical analysis of NRF, Geant4 is used to build the NRF backscatter detection model, the collimator structure of the electron accelerator and the background shield of the NRF signal are optimized and calculated, and the NRF process with 12C as the target element is simulated and calculated. The results show that the simulated characteristic energy spectrum of NRF signal is consistent with the theory, the designed background shielding scheme meets the needs of NRF signal identification and detection, and the simulated signal-to-noise ratio data provides the basis for the experiment.

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