Truong Thi Hong Loan, Vu Ngoc Ba, Dang Thi Thuy Dan, Vuong Minh Tri, Huynh Thi Yen Hong, Truong Huu Ngan Thy, Nguyen Thi Truc Linh, Le Cong Hao & Huynh Truc Phuong
Journal of Radioanalytical and Nuclear Chemistry 327, 609-616(2021)
Abstract:
In this work, the impacts of TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials) from fertilizers on soil and vegetables were estimated. We investigated both the activity concentration of the natural radionuclides and the annual effective dose rate due to the ingestion of vegetables in the crops using fertilizers at the agricultural zone of Hoc Mon, Ho Chi Minh City, Vietnam. The results show that there have not yet been signs of radioactive residues from using conventional fertilizers in agricultural land after a crop at the surveyed area and time. The radiological impact of surveyed vegetables was negligible to the public health.
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Impacts of Geant4 hadronic physics models on secondary particle productions in proton therapy simulations
Pham Thi Cam Lai, Vo Hong Hai, Nguyen Tri Toan Phuc
Radiation Physics and Chemistry 229 (2025) 112451
Abstract:
Monte Carlo simulations using the Geant4 toolkit are widely used in proton therapy to predict the dose distribution and secondary particle production. The choice of physics models used in the simulation can greatly affect the accuracy of the results. However, general hadronic models in Geant4 are not specifically tuned for medical physics regions and available experimental data are still limited. In this study, we investigated three different Geant4 hadronic physics models: BIC, BERT, and INCL++, by calculating the yields and kinematical distribution of the secondary neutron, gamma, and positron emitters as well as their incident energy dependence. The simulations were performed for a water phantom irradiated with 70 – 250 MeV proton beams. Our analysis revealed significant differences in the yields, angular, and energy distributions of emitted secondary particles between the three models. We also found a systematic underestimation of yields for the positron emitter 11C in the recent version 10.7 of Geant4. Overall, our study highlights the importance of carefully selecting a hadronic physics model for Geant4 simulations in proton therapy. Our findings also emphasize the need for a specifically tuned Geant4 hadronic model for proton therapy applications in order to consistently reproduce a wide range of important observables. More experimental data for proton-induced reactions in human tissue are critically needed to constrain and validate the suitable physics models for proton therapy simulation.
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Impact of Nonlocality Effects in Proton Optical Potential from Folding Model on p+ 16O Elastic Scattering at Low Energies
Nguyen Hoang Phuc, Nguyen Tri Toan Phuc & Do Cong Cuong
Braz J Phys 54, 226 (2024)
Abstract:
We employ the single folding model to calculate the optical potential (OP) for the p+16O scattering system, in which the exchange term of the OP is nonlocal. In most studies, this term is approximated to a local form to simplify the calculations. In this work, the folding OP, including the nonlocal exchange term, is constructed based on the CDM3Y3 effective nucleon-nucleon (NN) interaction. The Schrödinger equation for the nucleon-nucleus scattering with the nonlocal OP is solved exactly using the Lagrange-mesh R-matrix method. By comparing the scattering cross sections calculated with the nonlocal potential and the localized approximation, we can assess the impact of the nonlocality effects in proton-nucleus elastic scattering. The calculated results demonstrate that the nonlocality effect of the OP significantly influences the low-energy elastic scattering cross sections of p+16O .
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Nguyen Le Anh , Nguyen Hoang Phuc , Dao T. Khoa , Le Hoang Chien , Nguyen Tri Toan Phuc
Nuclear Physics A 1006 (2021) 122078
Abstract:
The proton radiative capture 12,13C(p, γ ) reactions at astrophysical energies, key processes in the CNO cycle, are revisited in the potential model with the proton-nucleus potential for both the scattering and bound states obtained in the folding model, using a realistic density dependent nucleon-nucleon interaction. For the consistency, this same folding model is also used to calculate the optical potential of the elastic p+12,13C scattering at energies around the Coulomb barrier. The folded p+12,13C optical potentials are shown to account well for both the elastic p+12,13C scattering and astrophysical S factors of the radiative capture 12,13C(p, γ ) reactions.
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Yu Nakazawa, Tai Thanh Chau, Yuki Fuji, Masahiro Ikeno, Satoshi Mihara, Masayoshi Shoji, Tomohisa Uchida, Kazuki Ueno, Myeong Jae Lee
Proceedings of Science, European Physical Society Conference on High Energy Physics - EPS-HEP2019 - 10-17 July, 2019
Abstract:
The COMET Phase-I experiment searches for a neutrinoless muon-to-electron conversion which has never been observed yet. The world’s highest intensity muon beam is applied, and it leads to an unacceptable trigger rate of O (106 ) Hz. For stable data collection, the trigger rate must be reduced to O(103)Hz. This requirement is met using online event classification in the detector system which holds 99% of signal events. This classification is performed by an FPGA-based trigger system, and its processing time is set to less than 5μs by a buffer size of the detector readout electronics. A prototype board for the trigger system was developed, and communica- tion systems for related electronics devices were also constructed. From test results, the total processing time is estimated to be 2.8 μ s , which meets the requirement. We have also devel- oped an online self-trigger system for cosmic-rays and confirmed the feasibility of this hardware logic. The trigger electronics were installed in a setup for cosmic-ray measurement, and the data acquisition was successfully done using the self-trigger system.
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N.T. Anh, L.X. Chung*, L.T. Anh, T.T. Anh, M. La Cognata, M.V. Dien, B.T. Hoa, N.T. Hung, P.D. Khue, D.T.K. Linh, N.T. Nghia, N.H. Phuc, N.T.T. Phuc, G.G. Rapisarda, M. Sferrazza, and D.T. Tran
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
Abstract:
A Faraday cup (FC) suitable for nA intensive beams has been developed to be used in nuclear reaction studies using the pelletron at Hanoi University of Science (HUS) - Vietnam National University (VNU). Firstly, the FC operation was tested with proton beams of 0.8 and 2.63 MeV energies bombarding a 0.081 μm 197 Au target. By varying the high voltage (-HV) applied to the FC’s repeller ring, current increase due to negative charge loss as secondary electron escape was investigated. Saturation was observed at about 50 V in both experiment and simulation using the CST Studio Suite software. Subsequently, the HV was set to -350 V to ensure the measuring current’s precision. Afterward, the FC was used in an experiment to measure the cross sections of p +12C elastic scattering with Ep =0.95-3.2 MeV at the laboratory angles of 50°, 106°, 120°, 130°, and 160° for its validation and further study for this reaction. Good agreement was obtained between our new data and those reported in the literature. The new data were analyzed with the R-matrix approach. The extracted level parameters are consistent with those of previous studies.
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