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 >>
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
Abstract:
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.
Benchmarking PHITS for radiation dose assessment from fly ash-blended concrete using MCNP6 and ResRad-Build
Lam Duy Nhat, Le Huu Loi, Le Quang Vuong, Vu Tuan Minh, Ho Van Doanh, Phan Long Ho, Tran Thien Thanh, Hoang Duc Tam
Applied Radiation and Isotopes, vol. 234, p. 112658, Apr. 2026
Abstract
In this study, the PHITS Monte Carlo code is applied for the first time to evaluate indoor radiation exposure associated with fly ash–blended concrete, and its performance is systematically benchmarked against the widely used ResRad-Build program and MCNP6 code. A reference room conforming to RP-112 dimensions (5 m × 4 m × 2.8 m) was modeled, and eight concrete mixtures containing 0–50% fly ash were investigated. The activity concentrations of 226Ra, 232Th, and 40K, along with material composition ratios and densities, were used as input parameters for simulations with PHITS, ResRad-Build, and MCNP6. The annual effective doses calculated using PHITS ranged from 0.378 to 0.489 mSv.y−1. The maximum relative deviations between PHITS and MCNP6 and between PHITS and ResRad-Build were 5.9% and 7.9%, respectively. PHITS exhibited the closest agreement with the reference dose estimate derived from measured activity concentrations, with a maximum relative deviation of 3.6%. These findings clearly demonstrate that PHITS is a highly reliable and effective tool for assessing indoor radiation exposure from building materials.
More details >>
Background subtraction using the SNIP method enhanced by the Levenberg–Marquardt algorithm
Anh Nhi Le, Thanh Tai Chau, Ngoc Ba Vu, Thien Thanh Tran, Le Hao Cong, Van Tao Chau
Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, 171544 (2026)
Abstract
In this study, a practical refinement of the SNIP method is proposed for background subtraction in HPGe γ-ray spectra. A single filter width determined from the detector specifications is used in Gaussian convolution to obtain preliminary peak parameters, which are then refined using the Levenberg–Marquardt (LM) algorithm to provide more reliable peak widths for SNIP background subtraction. The resulting method, referred to as LMSNIP, is evaluated using the 154Eu spectra measured at 25 cm and 5 cm. The reconstructed backgrounds are directly compared with those obtained using the adaptive SNIP approach, while the resulting net peak areas are compared with Genie2K. For the 25 cm spectrum, LMSNIP and adaptive SNIP provide generally similar background estimates. Under the more demanding 5 cm condition, however, LMSNIP yields a smoother and more stable baseline and generally better agreement with Genie2K for most investigated peaks. Additional validation using the 133Ba spectrum measured at 5 cm further shows that LMSNIP remains effective for a reference spectrum with different low-energy characteristics. These results support the applicability of LMSNIP to background reconstruction and net peak-area determination under the investigated close-geometry conditions.
More detail >>.
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)
Abstract:
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.
More detail >>
