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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Effects of soil erosion on natural radioactivity in water in a typical quarry lake in Vietnam based on model assessment
Van Thang Nguyen, Nguyen Phong Thu Huynh, Thi Yen Hong Huynh, Huu Ngan Thy Truong, Binh An Le, Truc Phuong Huynh, Cong Hao Le
Journal of Radioanalytical and Nuclear Chemistry
Abstract:
A quarry lake is a quarry that is filled with water after abandonment. In the lake water, natural radionuclides contaminate with a certain level, as a result of atmospheric deposition, groundwater diffusion, soil erosion, and sediment–water–air interaction. In this study, 40K, 226Ra, and 232Th were analysed for surface soil and water in a specific quarry lake in Vietnam. The seasonable variation of radioactivity in water was investigated. It was found that the activity concentration correlated with the TDS of water and the higher activity concentration was found in the wet season. The RUSLE model was used to predict the average annual rate of soil erosion in the study site. Based on the model prediction, the inflow rate of 40K, 226Ra, and 232Th in water were 4.73, 36.75, and 768.5 GBq y−1 respectively.
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Effects of single-particle overlap function on the 16O(p,2p)15N reaction
Nguyen Tri Toan Phuc, Vo Hong Hai
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Vu Ngoc Ba , Bui Ngoc Thien, Truong Thi Hong Loan
Nuclear Engineering and Technology Available online 2 July 2020
Abstract:
In this work, self-absorption correction factor related to the variation of the composition and the density of soil samples were evaluated using the p-type HPGe detector. The validated MCNP5 simulation model of this detector was used to evaluate its Full Energy Peak Efficiency (FEPE) under the variation of the composition and the density of the analysed samples. The results indicates that FEPE calculation of low gamma ray is affected by the composition and the density of soil samples. The self-absorption correction factors for different gamma-ray energies which was fitted as a function of FEPEs via density and energy and fitting parameters as polynomial function for the logarithm neper of gamma ray energy help to calculate quickly the detection efficiency of detector. Factor Analysis for the influence of the element composition in analysed samples on the FEPE indicates the FEPE distribution changes from non-metal to metal groups when the gamma ray energy increases from 92 keV to 238 keV. At energies above 238 keV, the FEPE primarily depends only on the metal elements and is significantly affected by aluminium and silicon composition in soil samples.
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