Bui Ngoc Thien, Vu Ngoc Ba, Nguyen Thi Thao Vy, Truong Thi Hong Loan
Chemosphere Volume 259, November 2020, 127432
Abstract:
In this study, soil-to-plant transfer factor and annual organ equivalent dose due to ingestion of natural radionuclides in 13 popular food crop samples in Ho Chi Minh city, Vietnam were estimated. The obtained data show that the radioactive elements transported from soil to plants play an essential role as indicators for the nutritional needs of plant and the ability to accumulate radioisotopes and heavy metal elements for environmental decontamination. It is found that B. alba and C. gigantean is useful for decontamination of high content potassium in soil, otherwise, P. fruticosa and C. gigantean may be used for soil with high concentration of 210Pb and 226Ra. In addition, biological effects of the plant ingestion in human body were assessed. The doses due to ingestion of food crop samples varied from organ to organ, depending on the organotrophic properties of the radionuclides. For examples, equivalent dose for 40K in large intestine is higher than other organs. In contrast, equivalent dose for 238U, 226Ra, 210Pb and 232Th were mostly at bone surface. In general, the obtained dose values of lower than the average value recommended by UNSCEAR for food crop ingestion pose no threat to the public’s health. However, close investigations are needed in the near future.
Establishment of an experimental system for X-ray fluorescence analysis with excitation using 3H/Zr source: Evaluation and applications
Van Thi Thu Trang, Nguyen Van Hanh, Huynh Truc Phuong
Spectrochimica Acta Part B: Atomic Spectroscopy 205 (2023) 106694
Abstract:
The goal of this study is to establish and assess an experimental apparatus for X-ray fluorescence analysis with elemental excitation in materials using a 3H/Zr source. The limits of detection and quantification, as well as analytical sensitivity, were estimated using a linear curve methodology. Furthermore, accuracy and precision were assessed by quantitatively analyzing the components of the reference material. The limits of detection and quantification of elements such as S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Ta, and Pb were estimated to range from 3.7 mg kg-1 to 573 mg kg-1, depending on the analyte. Analytical sensitivities were found to be between 1.2 and 867 cps/%. The measured elemental concentrations in the reference sample were compared with the inductively coupled plasma mass spectrometry method, and all bias (%) values were found to be lower than 10%. This study also determined the levels of Ca, Ti, Mn, and Fe in cement and K, Ca, Cr, Mn, Fe, and Zn in tea leaves. The results showed that the 3H/Zr source could detect and quantify components at concentrations of a few mg kg-1 or higher. X-ray fluorescence spectrometry is suggested for the analysis of the concentration of various elements in environmental, geological, food, and other samples.
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Enhancing Neutron/Gamma Discrimination in the Low-Energy Region for EJ-276 Plastic Scintillation Detector Using Machine Learning
IEEE Transactions on Nuclear Science
Abstract:
Pulse Shape Discrimination (PSD) techniques, particularly the widely employed charge integration ratio method (Q-ratio), have proven effective in discriminating fast neutrons from gamma rays in organic scintillation detectors. However, the effectiveness of Q-ratio diminishes in the low-energy region (below 150 keVee) due to overlapping signal, leading to a suboptimal Figure of Merit (FOM). In this study, we use machine learning (ML) technique, particularly the one-dimensional Convolutional Neural Network (1D-CNN), to enhance the neutron/gamma discrimination and compares the results with the traditional charge integration ratio in the low-energy region. Our investigation focuses on the EJ-276 plastic scintillator, a commercial product of ELJEN technology known for its good separation of gamma and fast neutron signals based on timing characteristics. Experimental data were acquired using 252Cf and 60Co radioisotope sources. A comprehensive comparative analysis between the traditional Q-ratio method and ML algorithms is conducted for the low energy region. Our main objective is to evaluate and enhance neutron/gamma discrimination capabilities of plastic scintillators in this low-energy region.
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Nguyen Tri Toan Phuc, R. S. Mackintosh, Nguyen Hoang Phuc, and Dao T. Khoa
ABSTRACT:
Background: A recent coupled-reaction-channel (CRC) study shows that the enhanced oscillation of the elastic 16O+12C section at backward angles is due mainly to the elastic α transfer or the core exchange. Such a process gives rise to a parity-dependent term in the total elastic S matrix, an indication of the parity dependence of the 16O+12C optical potential (OP).
Purpose: To explicitly determine the core exchange potential (CEP) induced by the symmetric exchange of the two 12C cores in the elastic 16O+12C scattering at Elab=132 and 300 MeV and explore its parity dependence.
Method: S matrix generated by CRC description of the elastic 16O+12C scattering is used as the input for the inversion calculation to obtain the effective local OP that contains both the Wigner and Majorana terms.
Results: The high-precision inversion results show a strong contribution by the complex Majorana term in the total OP of the 16O+12C system and thus provide for the first time a direct estimation of the parity-dependent CEP.
Conclusions: The elastic α transfer or exchange of the two 12C cores in the 16O+12C system gives rise to a complex parity dependence of the total OP. This should be a general feature of the OP for the light heavy-ion systems that contain two identical cores.
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Elastic and Inelastic Alpha Transfer in the 16O+12C Scattering
Nguyen Tri Toan Phuc, Nguyen Hoang Phuc, Dao Tien Khoa
Communication in physics, Vol.31, No 4(2021)
Abstract:
The elastic scattering cross section measured at energies E≲10 MeV/nucleon for some light heavy-ion systems having two identical cores like 16O+12C exhibits an enhanced oscillatory pattern at the backward angles. Such a pattern is known to be due to the transfer of the valence nucleon or cluster between the two identical cores. In particular, the elastic α transfer has been shown to originate directly from the core-exchange symmetry in the elastic 16O+12C scattering. Given the strong transition strength of the $2^+_1$ state of $^{12}$C and its large overlap with the $^{16}$O ground state, it is natural to expect a similar α transfer process (or inelastic α transfer) to take place in the inelastic 16O+12C scattering. The present work provides a realistic coupled channel description of the α transfer in the inelastic 16O+12C scattering at low energies. Based on the results of the 4 coupled reaction-channels calculation, we show a significant contribution of the α transfer to the inelastic 16O+12C scattering cross section at the backward angles. These results suggest that the explicit coupling to the α transfer channels is crucial in the studies of the elastic and inelastic scattering of a nucleus-nucleus system with the core-exchange symmetry.
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Effects of soil nutrition on some elements' uptake by plants and human health-risk assessment
Ngoc Ba Vu, Van Thang Nguyen, Huynh Truc Van & Thi Hong Loan Truong
Journal of Radioanalytical and Nuclear Chemistry
Abstract:
Some elements in fertilizers can accumulate in soil, transfer to vegetables and pose a number risks to humans and the environment. This study determined several elements (Cl, Co, Cr, Fe, Mn, Na, Sc, Sb and Zn) in the system of fertilizers-soil-vegetables samples by using the k 0 -standardized instrumental neutron activation analysis (k0 -NAA). The results indicate that the elemental composition in plants is influenced by the source of nutrients, whether from soil or fertilizers. Target hazard quotients (THQ) were lesser than 1 for all vegetables, indicating that consumers were at least a risk when consuming individual vegetables.
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