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The COMET Collaboration


The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminum nucleus (μe conversion, μN eN); a lepton flavor- violating process. The experimental sensitivity goal for this process in the Phase-I experiment is 3.1 × 1015, or 90% upper limit of a branching ratio of 7 × 1015, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the μe conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.

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Trần Thiện Thanh, Văn Tấn Phát, Lê Hoàng Minh, Huỳnh Đình Chương, Võ Hoàng Nguyên, Nguyễn Trí Toàn Phúc, Lê Quang Vương, Nguyễn Duy Thông, Châu Văn Tạo
Sci. Tech. Dev. J. - Nat. Sci.; 4(2):Online-First
Các thông số đặc trưng của vật liệu liên quan đến tương tác của bức xạ photon như: hệ số suy giảm khối, số nguyên tử hiệu dụng, mật độ electron là những dữ liệu cần thiết được yêu cầu trong nhiều công việc như chẩn đoán và xạ trị ung thư, chiếu xạ công nghiệp, tính liều lượng bức xạ, che chắn phóng xạ, phân tích hàm lượng nguyên tố và đồng vị phóng xạ. Trong bài báo này, các mô hình lý thuyết như tham số dạng phi tương đối tính (NRFF), tham số dạng tương đối tính (RFF), tham số dạng hiệu chỉnh (MFF) được sử dụng để tính toán tỉ số Rayleigh-Compton đối với các nguyên tố có 6<=Z<=82 tại năng lượng 59,5 keV. Kết quả chỉ ra rằng có sự khác biệt lớn giữa các mô hình tính toán đối với bia có số nguyên tử lớn. Giá trị trung bình của tỉ số Rayleigh-Compton theo số nguyên tử Z được làm khớp hàm bậc hai mô tả khá tốt quy luật phụ thuộc này với hệ số tương quan R2 =0,996. Bên cạnh đó, hệ đo thực nghiệm cũng được thiết kế và thực nghiệm đo đạc đối với một số bia như nhôm, đồng và chì tại góc tán xạ 150o sử dụng nguồn 241Am bằng đầu dò Si(Li) để kiểm chứng với kết quả tính toán lý thuyết. Kết quả thực nghiệm ban đầu đã chỉ ra rằng có sự phù hợp tốt giữa các mô hình lý thuyết với các bia nhôm, đồng và chì với độ sai biệt dưới 20%. Trong tương lai, chúng tôi sẽ tiến hành thực nghiệm với nhiều dạng bia khác nhau để đánh giá chi tiết hơn.
Từ khoá: NRFF, RFF, MFF, Tỉ số Rayleigh-Compton, đầu dò Si(Li)
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Nguyen Anh TUAN and Chau Van TAO

Nuclear Technology & Radiation Protection: Year 2020, Vol. 35, No. 1, pp. 36-41


An electron beam from the UELR-10-15S2 accelerator (average energy of 9.92 ± 0.48 MeV) was applied to irradiate food and medical items at the Research and Development Center for Radiation Technology, Vietnam Atomic Energy Institute, Vietnam. The materials are under an electron beam window, such as irradiation products, conveyor, magnet and shielding mate- rial for the magnet coil, bombarded by electrons and generated X-ray (bremsstrahlung effect). In this article, X-ray conversion efficiency from polypropylene, aluminum, iron, and lead bombarded by an electron beam from the UELR-10-15S2 accelerator is measured by the film dosimeter and simulated by the MCNP4c2 code, and there is good agreement between the calculation and measurement results. The results show that X-ray conversion efficiency is the highest from lead (4.3 %), so the gamma - neutron reaction (Q-value of –6.74 MeV for 207Pb) has to be studied in food and medical items irradiated by a 10 MeV eelectron beam.

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Nguyen Huu Quyet, Le Hong Khiem, Trinh Thi Thu My, Nguyen Thi Bao My, Marina Frontasieva, Inga Zinicovscaia, Nguyen An Son, Tran Thien Thanh, Le Dai Nam, Khuat Thi Hong, Nguyen Ngoc Mai, Trinh Dinh Trung, Duong Van Thang, Nguyen Thi Thuy Hang

Environmental Engineering and Management Journal


Atmospheric deposition of chemical elements in the Hanoi region has been investigated in this study based on moss biomonitoring. Twenty-seven Barbula indica moss samples were collected from the end of 2016 to the beginning of 2017, and the concentrations of 33 chemical elements in the samples were determined by instrumental neutron activation analysis. The results show that Hanoi’s air is highly polluted with Zn, Ba and Ta, and slightly polluted with Al, Cl, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, As, Cd, Sb, La, Ce, Sm, Gd, Tb, Yb, Hf, Th and U. A determination of the possible pollution sources has been made for the analyzed elements; namely: coal and oil combustion are the main sources of V, Ni, Co and As; vehicle exhaust and non-exhaust sources, as well as industrial emissions, are the main sources of Mn, Co, Cd and Ba; construction dust is the source of Ca, Mg and Sb; various industries are the sources of Cr and Ni; the dust from cement kilns and ash from biomass burning is responsible for K and Cl; two-stroke motor vehicles, galvanizing factories and tire wear are the sources of Zn; and Br may be emitted from burning wastes.


Link of this article will be updated.

Background Radiation in some Quarries and Quarry Lakes in Binh Duong Province, Vietnam

Van Thang Nguyen, Nguyen Phong Thu Huynh, Huynh Thi Yen Hong, Truong Huu Ngan Thy, Huynh Truc Phuong, Cong Hao Le

Journal of Radioanalytical and Nuclear Chemistry(2022)


Operation of some quarries can release radioactive materials from the deep soil to other environments that potentially impact human health. The present study investigated concentrations of radon and other radionuclides in surface soil, air, and water around two quarries in the south of Vietnam. Indoor radon concentrations ranged between 6.19 Bq m-3 and 20.6 Bq m-3. In surface soil, the average concentrations of 40K, 226Ra, and 232Th were 387, 36.5, and 44.5 Bq kg− 1, respectively. In surface soil, the average values of radioactivity found for 40K, 226Ra, 238U, and 232Th were 2.65, 1.23, 1.12, and 1.22 mBq l-1, respectively. The results show that the radioactive levels in the quarry region are found higher than in the nearby area. However, these levels are not enough for a recommendation for public health.

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Phan Long Ho, Le Dinh Hung, Vu Tuan Minh, Dang Van Chinh, Tran Thien Thanh, Chau Van Tao

Science of The Total Environment, Available online 18 June 2020, 140291

This paper presents information on the concentration of radioactivity and chemicals at 12 water stations that used groundwater as their raw water supply source. The groundwater's radioactivity was higher than the treated, tap, and surface water, but lower than the national and international recommendations. At five stations (41.7%), the gross alpha contents were higher than the levels advised by Vietnam's regulations, but met the WHO and IAEA's recommendations. The mean active (Bq L−1) gross alpha, gross beta, Ra-224, Ra-226, and Ra-228 were 0.093 ± 0.012, 0.221 ± 0.020, 0.031 ± 0.004, 0.028 ± 0.004, and 0.035 ± 0.001, respectively. The contribution of Ra-226 to the gross alpha was in a range of 23%–60% (r = 0.91, p value <.001), and the ratio of Ra-226/Ra-228 ranged from 0.49–1.06. For the treated and tap water, each age groups' annual committed effective dose was lower than the international regulations. The concentration of the total dissolved solids, sulfate, chloride, sodium, barium, and manganese met the national regulations. However, during the rainy season, the surface water in the area was affected by saltwater intrusion, with salinity up to 4.1‰. Discriminant analysis was applied to study the differences among the water groups. As a result, the treated and tap water were separated from the others.
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