Distribution characteristics of radionuclides (²²⁶Ra, ²³⁴U, and ²³⁸U) and ratios (²²⁶Ra/²³⁴U, ²²⁶Ra/²³⁸U, and ²³⁴U/²³⁸U) in quarry lake environment: experimental and model assessment

Van Thang Nguyen, Cong Hao Le

Journal of Radioanalytical and Nuclear Chemistry

Abstract:

The abandonment of stone quarries establishes a quarry lake ecosystem that includes soil, water, fish, and vegetarian cover. The activity concentrations (ACs) of natural radionuclides in the waters of several quarry lakes worldwide have not been investigated. In addition, the features of radionuclides, such as distribution, seasonal variability, and health risks, have not been studied. In this study, the ACs of ²²⁶Ra, ²³⁴U, and ²³⁸U were measured in a typical quarry lake in Vietnam with an area of approximately 4000 m². The average ACs of ²²⁶Ra, ²³⁴U, and ²³⁸U were 8.3, 13.8, and 17.7 mBq L⁻¹, respectively. The ratios of ²²⁶Ra/²³⁴U, ²²⁶Ra/²³⁸U, and ²³⁴U/²³⁸U were 0.47, 0.6, and 0.79, respectively. A linear correlation was found between ACs and water depth. The ACs predicted by the QWASI (Quantitative Water, Air, Sediment Interaction) model agree with the measured values.

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Yuki Fujii, Yu Nakazawa, Ewen Lawson Gillies, Eitaro Hamada, Masahiro Ikeno, MyeongJae Lee, Satoshi Mihara, Yuta Miyazaki, Masayoshi Shoji, Chau Thanh Tai, Tomohisa Uchida and Kazuki Ueno for COMET Collaboration

DOI: 10.1109/NSSMIC.2018.8824619

Abstract:

A COMET Experiment Phase-I is designed to search for a muon to an electron conversion with a 100 times better sensitivity than the current upper limit on its branching ratio in order to investigate the new physics beyond the standard model. To achieve such an unprecedented sensitivity, a high intensity muon beam is mandatory. In consequence, an extremely high hit rate is predicted and it can cause a high trigger rate more than tens of kHz dominated by the background events. Then the high trigger rate would lead to the severe dead-time in the data acquisition. Therefore it is essential for a success of the experiment to reduce the trigger rate down to a few kHz within a processing time shorter than 5 μs while maintaining the signal efficiency high enough. We are developing an event classification algorithm utilising a CDC hit information and a dedicated fast online trigger system to accomplish this aim. The event classification based on a boosted decision tree shows 3.8 kHz of trigger rate, which almost satisfies the rate requirement, with a good compatibility to the trigger electronics. The total processing time to generate the trigger decision is estimated to be ~3 μs which also fulfils the timing requirement.

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Development Of FPGA-Based Nuclear Electronics Using NI MyRIO Hardware For Small-Scale Radiation Detector Systems

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IEEE Transactions on Nuclear Science

Abstract:

This study presents advancements in coincidence electronics and a Pulse Height Analyzer (PHA) utilizing commercial FPGA-based (Field-Programmable Gate Array) hardware for radiation scintillation detectors. The hardware, based on a cost-effective NI myRIO device, integrates an FPGA, ARM Cortex-A9 processor, analog input (AI), digital input and output (DIO), and USB/wireless connectivity with a host computer. LabVIEW codes developed on the LabVIEW™ platform are implemented in the NI myRIO hardware for seamless integration and interfacing with a computer. The performance of the FPGA-based coincidence electronics is assessed through an experimental setup measuring the gamma-gamma angular distribution of a 22 Na radioisotope source. Similarly, the FPGA-based PHA is tested with a CsI(Tl) detector, and its energy resolution is compared to a commercial EASY-MCA 2K from AMETEK Inc.

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Development and implementation of a wireless real-time radiation monitoring system for LINAC beam delivery monitoring

Vo Hong Hai, Phuc Tri Toan Nguyen and Hieu Trung Nguyen

Science & Technology Development Journal 2024, 27():1-7

Abstract:

Introduction: In this work, we developed a wireless, remote, real-time radiation monitoring system designed to oversee beam delivery in a radiation therapy room equipped with a medical linear accelerator (LINAC).

Methods: This system utilizes a Geiger-Müller detector paired with embedded electronic hardware to accurately record radiation count rates in real-time. The data collected by this system are transmitted through LAN/WAN networks to the internet, ensuring instantaneous accessibility. In addition, a web server and mobile application were developed to display, receive, and archive the data from the radiation counter.

Results: Our system was deployed in the radiation therapy room of the Oncology Hospital in Ho Chi Minh City, demonstrating a remarkable data reception rate of up to 99.8% over a three-day test period from June 27^th to 29^th, 2022. The system effectively identified beam-on instances and provided precise measurements of the number and duration of beam-on events.

Conclusion: This study demonstrates the feasibility of remote real-time radiation monitoring in medical settings and highlights the potential for enhancing radiation safety and treatment efficacy in external beam radiotherapy.

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Determining the thickness of a thin aluminum sheet using the transmission measurement of X-rays with varying energies: A comparative analysis between calibration curve fitting and artificial neural network approaches

Nguyen Thi Truc Linh, Nguyen Huynh Duy Khang, Le Thi Ngoc Trang, Huynh Dinh Chuong, Tran Thien Thanh, Huynh Truc Phuong, Hoang Duc Tam

Nuclear Instruments and Methods in Physics Research A

Abstract:

This study proposes an innovative configuration for thickness measurement based on X-ray transmission, intending to improve the precision of measuring thin aluminum sheets. In this configuration, an activation sample containing Zr, Sb, and Ba elements is irradiated by 59.54 keV gamma rays emitted from three 241Am radioactive sources with a total activity of 1.78 GBq. Subsequently, the activation sample emits fluorescent Xrays at energy levels of 15.78 keV (Zr-K_α1,2), 17.67 keV (Zr-K_β1), 26.36 keV (Sb-K_α1,2), 29.73 keV (Sb-K_β1), 32.2 keV (Ba-K_α1,2), and 36.38 keV (Ba-K_β1). These X-rays are collimated into a narrow beam, which then penetrates through an absorbing sample, and is ultimately recorded by a Si(Li) detector. Two different approaches are investigated to determine the thickness of absorbing samples including Calibration Curve Fitting (CCF) and Artificial Neural Network (ANN). The CCF approach requires constructing linear calibration curves for establishing the relationship between lnR (R is the ratio of the peak areas in measurements with and without absorbing sample) and the thickness of the absorbing sample at each X-ray energy level. The sample thickness is then determined by calculating a weighted average of the measured thicknesses associated with all analyzed energy levels. This approach requires in-depth understanding of radiation physics and proficiency in X-ray spectrum analysis. Meanwhile, the ANN approach uses raw spectra obtained by the Si(Li) detector to predict the thickness of aluminum sheets, facilitating analysis without requiring human intervention. The reliability of these approaches is evaluated through experimental measurements on aluminum sheets with thicknesses ranging from 0.064 cm to 1.074 cm. The results indicate that using X-rays with many different energies leads to superior accuracy in thickness measurements compared to using X-rays with a single energy. Besides, both the CCF and ANN approaches yield relative deviations of less than 3% between the predicted and reference thicknesses. It is important to emphasize that the ANN approach represents a promising solution for automated analysis without the intervention of experts.

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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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