COMPARATIVE STUDY OF SIMULATION AND EXPERIMENT IN DETERMINING 192Ir SOURCE STRENGTH FOR BRACHYTHERAPY QUALITY ASSURANCE
Tran Thi Bao Ngoc, Phan Quoc Uy, Le Quang Vuong, Tran Thien Thanh, Chau Van Tao
Radiation Physics and Chemistry
Abstract:
This research is of paramount importance as it combines experimental measurements and Monte Carlo simulation to determine the air kerma strength of the 192Ir source, which plays a crucial role in dose calculations for brachytherapy treatment planning. The air kerma strength represents the source strength value, directly influencing the accuracy of dose calculations in cancer treatments. Verifying the source strength during each source exchange is essential to the quality assurance process.
In this study, the 192Ir Gammamed Plus source, provided by Varian, was used to calculate the air kerma strength through experimental measurements and Monte Carlo simulation. The measurements were conducted on a brachytherapy system with an HDR 1000 Plus well-type ionization chamber and source tube 70010 from Standard Imaging. Using the MCNP6 code, we constructed a model equivalent to the experimental system, consisting of the source geometry, source tube, and well-type chamber, with source self-absorption also considered.
The air kerma strength measurements differed from the certified value by less than 2%, within the allowable range according to the AAPM TG40 recommendations. The experimental and simulation methods showed strong agreement, with less than 4.1% discrepancies. Considering source self-absorption, the air kerma strength calculation for the 192Ir source was consistent across both methods. The findings of this study validate that we successfully built an experimental system model using the Monte Carlo simulation with the MCNP6 code. This model can be further developed for future research.
More detail >>
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 (μ–e conversion, μ−N → e−N); a lepton flavor- violating process. The experimental sensitivity goal for this process in the Phase-I experiment is 3.1 × 10−15, or 90% upper limit of a branching ratio of 7 × 10−15, 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 μ–e 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.
More detail >>
Combination of experimental and simulation methods for determination of effective atomic number by Rayleigh-Compton scattering technique
Le Hoang Minh, Van Thi Thu Trang, Tran Thien Thanh
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY 2025
Abstract:
This paper presents the gamma scattering technique to determine substance' component concentrations. The experimental and simulated R/C ratios of binary oxide samples (Fe2O3and SiO2) were measured. The concentration of each element were interpolated, with a bias relative less than 5% for the elements in the reference samples. The elements' experimental and theoretical Rayleigh-Compton ratio values had a robust relationship in the equation RexpR/C=1.03×RtheoR/C (n = 11; r = 0.99; p-value < 0.01). The Zeff interpolation results and the calculation results from the theoretical formulas have good agreement with an average difference of 5%.
More detail >>
Bulk density determination of concrete by gamma-ray transmission using a 137Cs source and NaI(Tl) spectrometry: MCNP-based calibration and experimental validation across varying aggregate compositions
Huynh Dinh Chuong, Van Thi Thu Trang, Vo Hoang Nguyen, Le Thi Ngoc Trang, Nguyen Thi Truc Linh, Tran Thien Thanh
Radiation Physics and Chemistry, Vol 248(2026),114145
Abstract:
This paper presents a gamma-ray transmission method for the non-destructive determination of concrete bulk density. The experimental setup comprises a137Cs source, a NaI(Tl) detector, and lead collimators arranged in a narrow-beam transmission geometry. An MCNP model was developed to closely replicate the measurement configuration and was subsequently used to generate pulse-height spectra for elemental and concrete specimens covering densities of 2.10 – 8.96 g cm−3 and thicknesses of 1 – 15 cm. From each spectrum, the net area of the 661.7 keV peak was extracted, and the attenuation indicator R was defined as the ratio of the peak areas recorded with and without the specimen. The simulations were benchmarked against measurements for aluminum and copper reference specimens at different thicknesses, showing good agreement in spectral response and relative deviations between simulated and experimental R values below 0.8%. Using the simulated R dataset, a linear calibration curve was established, enabling concrete bulk density to be determined without prior knowledge of the elemental composition. The method was applied to 22 concrete specimens fabricated with different aggregate systems, including ordinary concretes and concretes incorporating heavyweight additives (e.g., barite, Bi2O3, Fe2O3, and steel chips). These specimens covered densities of 2.2 – 2.6 g cm−3 and thicknesses of 3 – 15 cm. Each specimen was measured at nine locations to assess spatial variability, and the weighted mean was taken as the representative bulk density. The resulting densities agree well with reference values obtained from mass-to-volume measurements, with relative deviations not exceeding 3.74% for all specimens. A coverage-probability–based statistical framework, augmented by additional sampling, was introduced to assess and improve measurement reliability when structural heterogeneity produces spatial variations in the inferred density. These preliminary results demonstrate that the proposed method is reliable and well suited for rapid concrete quality control.
More detail>>
Nguyen Anh TUAN and Chau Van TAO
Nuclear Technology & Radiation Protection: Year 2020, Vol. 35, No. 1, pp. 36-41
Abstract:
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.
More detail >>
