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KHOA VẬT LÝ - VẬT LÝ KỸ THUẬT

BỘ MÔN VẬT LÝ HẠT NHÂN - NGÀNH KỸ THUẬT HẠT NHÂN - NGÀNH VẬT LÝ Y KHOA

Huynh Dinh Chuong, Nguyen Thi Hai Yen, Nguyen Thi My Le, Hoang Duc Tam

Applied Radiation and Isotopes Available online 29 April 2020, 109197

Abstract:

This study proposes an approach to determine the density of a liquid based on the gamma scattering method. The liquids used to determine density were poured in a cylindrical tube. This approach requires that the ratio R (the ratio of area under a single scattering peak for a liquid to that for water) increase linearly with an increase in the density of the liquid. In a certain range of density, a linear relationship was obtained between the ratio R and density, as described by a linear calibration curve with coefficients of slope and intercept, for the investigated tube diameters. In particular, the values of the slope and intercept could be expressed as mathematical functions of the diameter of the tube. For a given tube, the coefficients of slope and intercept of the linear calibration curve were obtained based on these functions, which helped determine the density of the liquid. The reliability of the proposed approach was evaluated by using it to calculate the densities of five liquids—n-hexane, diethyl ether, acetonitrile, toluene, and glycerol—using tubes with inner diameters of 1.8 cm, 2.25 cm, and 2.68 cm. The results show that the maximum relative deviation between the reference and the measured densities was 4.3%.

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Huynh Dinh Chuong, Le Thi Ngoc Trang, Hoang Duc Tam, Vo Hoang Nguyen, Tran Thien Thanh

NDT & E International Available online 4 May 2020, 102281

Abstract:

This study proposes a new approach to determine the thickness of the material plate. This approach uses Monte Carlo simulation to construct the calibration curve of the ratio R versus the thickness of the material plate (R is the ratio of area under a scattering peak for a given thickness to that for a saturation thickness). Using this calibration curve, the unknown thickness of a material plate is determined by experimentally measuring the ratio R. To validate the proposed approach, we performed 39 measurements for 13 aluminum samples with thicknesses in the range of 7.00 mm–35.20 mm. The results showed that except for two measurements with relative deviations of 5.45% and 6.17%, the relative deviation for the remaining measurements is less than 5%. Besides, the method for estimating the maximum measurable thickness with the desired deviation was presented, which shows good agreement between theoretical calculation and experimental value. The obtained results are the basis for completing the thickness measurement system using semi-empirical methods in further studies.

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 Phuong Truc Huynh, Trinh Pham Ngoc Tran, Binh Thanh Dinh, Linh Thi Truc Nguyen, Loan Thi Hong Truong, Anh Tuan Tran, Dung Manh Ho, Dong Van Nguyen

Journal of Radioanalytical and Nuclear Chemistry (2020) 324:663–671

Abstract:

The aim of this study was to nd trace elements that increase risk of breast cancer based on the deviation of the concentra- tion of trace elements in the ngernail collected from the women with breast cancer and the normal women. The study was conducted with 10 elements (As, Au, Br, Co, Cr, Fe, Sb, Sc, Se, and Zn) using k0-INAA and statistical analysis method. Signi cant di erences (P < 0.05) were found for Cr, Fe, Sc and Zn between the case and the control groups. A signi cant correlation between Fe and Zn has found for the normal women, but this disappears in the women with breast cancer. On the contrary, a signi cant correlation between As and Cr has found in the case group, but no such correlation has noticed for the control group. The elements Cr, Fe, and Zn may be associated to the risk of breast cancer.

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Tran ThienThanh, Le Hoang Minh, Nguyen Quoc Bao Cuong, Huynh Dinh Chuong, Nguyen Duy Thong, Vo Hoang Nguyen, Phan Long Ho, Chau Thanh Tai,  Chau Van Tao

NIM A Available online 23 April 2020, 163995

Abstract:

Experimental data of Rayleigh to Compton scattering ratios depending on the effective atomic number of the fifteen powder samples in the range 10 < Z < 30 obtained at an energy of 59.54 keV using six well-known methods are presented in this article. In this study, a Si(Li) detector is placed at a scattering angle of 150 degrees to detect emitting signals from the interaction of incident gamma rays and powder samples. A new fitting procedure with the least squares method was used to fit the Compton peak using a Voigt function and the Rayleigh peak using a Gaussian function by Root software. The ten calibrating samples provided results that were in good agreement with the fitting procedure for all methods using linear functions. The estimated values of the Rayleigh to Compton scattering ratio using the effective atomic numbers were compared to the theoretical calculation. Furthermore, the best solution for the interpolated effective atomic number of the six methods was found and confirmed with the maximum relative deviation lower than 4% for five analysed samples.

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Huynh Dinh Chuong, Le Thi Ngoc Trang, Vo Hoang Nguyen, Tran Thien Thanh

Applied Radiation and Isotopes, Available online 10 April 2020, 109179

Abstract:

In present work, the validity of the virtual point detector (VPD) model for the NaI(Tl) detectors is studied and confirmed in the photon energy range of 60-1408 keV. The full energy peak efficiency (FEPE) of two NaI(Tl) detectors, which have scintillation crystal dimensions of 5.08×5.08 cm and 7.62×7.62 cm respectively, is measured for “point-like” radioactive sources on the symmetry axis with source-to-detector distances in the range of 2-40 cm. It is found that the VPD model is valid to fit too well to the experimental FEPE for the two surveyed NaI(Tl) detectors. The dependence of the VPD position on the incident photon energy for the NaI(Tl) detectors with different scintillation crystal dimensions is shown based on experimental data. A semi-empirical equation involving incident photon energy and source-to-detector distance is proposed to calculate the FEPE for the NaI(Tl) detectors. The calculated results for the two surveyed NaI(Tl) detectors by this equation are in a good agreement with experimental results for photon energies in the range of 344-1408 keV. However, the difference between experimental and calculated results is quite significant for source-to-detector close geometries for photon energies lower than 344 keV.

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The COMET Collaboration

Abstract:

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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