Journal of Radioanalytical and Nuclear Chemistry最新文献

A dual-plane Compton imaging detector previously developed for prompt gamma imaging has been further tested and calibrated for quantitative radioactivity determination, specifically to assess radioactive debris from a reactor fuel element. The debris piece contains uranium isotopes and several long-lived fission products, including cesium-137 (Cs-137). The detector consists of two pixelated planes of cadmium-zinc-telluride (CZT) crystals which record gamma ray events interacting within these volumes. In addition to the energy spectrum obtained by pulse height analysis, the time-stamped events from each detector pixel are sorted by location into 3 categories for post-processing: intra-plane, inter-plane, and coincidence. An image reconstruction software enables spatial localization of the select gamma ray peak(s) from the spectrum, thereby separating the gamma ray by specific isotopes. We used the camera to image a small piece of debris for demonstration purposes. A measurement was performed alongside a high purity germanium (HPGe) detector, which could determine the isotopes' absolute activities and be used as a reference for the camera. In addition, a known isotopic point source was used to calibrate the camera’s energy detection efficiency in the same measurement geometry, correlating the image pixel intensity to the isotopic activity.

Neuroendocrine tumors (NETs) as compared to its octreotide (NOC) counterpart when labeled with In-111 and Tc-99m. This study was aimed to develop easy to use, cost effective, and commercially available diagnostic kit of [^99mTc][Tc-HYNIC-TATE] (Tyr3-Octreotate) indigenously to diagnose neuroendocrine tumors in Pakistan. HYNIC-TATE cold kit was optimized at 20µg of peptide (Octreotate), following co-ligand exchange labeling approach using EDDA/TRICINE (3:6 mg) while heating at 90 °C for 20 min. Radiochemical purity of [^99mTc][Tc-HYNIC-TATE] was > 98 ± 0.14% when labeled with 550–850 MBq of Tc-99m and stable upto 12 h. Preclinical & clinical investigations validated the higher sensitivity and specificity of the developed kits for spot-on detection of neuroendocrine tumours (NETs).

Graphical Abstract

A reference material of Coffea arabica leaves from a farm with organic management certification was developed at CENA/USP. Neutron activation analysis was used to determine chemical elements, including assessment of homogeneity and stability. The material was characterized for Ba, Br, Ca, Co, Fe, K, La, Na, Rb, Sc, Sm, Sr and Zn. Reference values were assigned to all elements except Co and Zn whose homogeneous distribution in the material could not be confirmed.

In this study, the mechanism by which Kocuria rosea immobilizes U(VI) ions in water via phytate hydrolysis was investigated. The results showed that the optimal initial pH value is 6.0 for uranium removal by K. rosea in the presence of phytate, SEM showed that phytate addition to the test system enhanced the particle sizes of uranium-containing crystalline products, XRD and XPS analyses revealed that in the presence of phytate, K. rosea precipitated uranium primarily as H₂(UO₂)₂(PO₄)₂·8H₂O, CaU(PO₄)₂ and Na(UO₂)(PO₄)·3H₂O. FT-IR spectroscopy also indicated that phytate hydrolysis resulted in the release of more phosphorus groups, thus enhanced the interaction between uranium and K. rosea. Taken together, phytate enhanced biomineralization while reducing the restoration cycle of uranium and increasing the size of uranium-containing crystalline particles in the products.

In this research, the polydopamine coating method and acrylonitrile addition grafting method were used to obtain corn stalk carbon modified by –C≡N (CSC@CN). Next, the amidoxime-modified corn stalk carbon was synthesized using a hydroxylamine hydrochloride electrophilic addition method. This modified carbon material was used as an adsorption material of uranyl ions. A series of experimental results showed that at a temperature of 298 K, the solid-liquid ratio is 0.4 g/L, the initial concentration of uranium solution is 150 ppm with pH = 6, and the adsorption time is 420 min, achieving the maximum adsorption capacity of uranium of 230.58 mg/g. The kinetic study of the adsorption process showed that it conformed to the quasi-second-order kinetic model, which belonged to chemisorption, and the Langmuir model, which belonged to monolayer adsorption. Thermodynamic studies showed that the standard enthalpy change (Delta {text{H}}^{0} ; < ;0), indicating that the adsorption process was endothermic. The standard Gibbs free energy change (Delta {text{G}}^{0} ; < ;0), indicating that the adsorption reaction was spontaneous. Furthermore, entropy (Delta {text{S}}^{0} > 0), suggesting an increase in confusion at the solid-liquid interface during the adsorption process.

The cross section of ⁸⁵Rb(n,2n)^84mRb and ⁸⁵Rb(n,p)^85mKr reactions were measured at neutron energy range 12–20 MeV using activation analysis followed by off-line γ-ray spectroscopic technique. The quasi mono-energetic neutrons were produced through ⁷Li(p,n)⁷Be reaction. The measurements were done relative to ²⁷Al(n,α)²⁴Na reference monitor reaction cross section. The detailed uncertainty propagation from the attributes present in measurements was performed using covariance analysis. The γ-ray self-attenuation and background low neutron energy corrections were performed in the measurement studies. Theoretical calculations were performed by TALYS-1.96 nuclear code. The comparison of measured values with the available data in EXFOR database and evaluated data from JENDL-5 and EAF-2010 shows the measured cross section values of ⁸⁵Rb(n,p)^85mKr reaction were slightly higher than the published values, evaluated data and theoretical data while for ⁸⁵Rb(n,2n)^84mRb, the measured values were consistent with the published data.

The main goal of the study is to evaluate the activity level of gamma radiation from uranium (²³⁸U), thorium (²³²Th) and potassium (⁴⁰K) using gamma spectrometry with NaI(Tl) detector and concentration of heavy metals (HM), i.e. lead (Pb), cadmium (Cd), nickel (Ni), cobalt (Co), iron (Fe) and chromium (Cr) using atomic absorption spectroscopy (AAS) in soil samples taken from different places of Saraswati River, Yamuna Nagar, Haryana in India. The mean value of ²³⁸U, ²³²Th, ⁴⁰K, radium equivalent activity and air-absorbed dose rate lies within the safe limit. The mean value of Radium equivalent activity and air-absorbed dose rate is within safe limits. The mean value of the corresponding HM is Fe > Pb > Ni > Co > Cd > Cr. The findings indicate that the level of HM in the soil sample of the study area is considerably below the acceptable limit.

The standard calibrator–instrumental neutron activation analysis method was used to characterize the mass fractions of Co, Cr, and Zn in a lake sediment certified reference material (CRM) developed by the Korea Research Institute of Standards and Science. The method was validated for each element and sediment matrix, and the CRM analysis was repeated to ensure reproducibility and address potential matrix interferences. To verify measurement reliability, quality control samples were also assessed. For lake sediment samples with a small Zn peak and dominant adjacent peaks of Eu and Sc, sequential measurements were performed to obtain accurate Zn concentrations. The optimal measurement timing was when the Sc peak sufficiently decayed and the intensity of the Zn peak remained larger than that of Eu. Moreover, an appropriate fitting program capable of deconvoluting complex peak regions is necessary.

The results of a pilot study performed on data from selected dwellings in Slovakia suggested that the best agreement between measured and calculated annual mean indoor radon activity concentration (RAC) were obtained by using seasonal correction factors (SCF) determined for winter season. In this paper, SCF was applied on results obtained during a new, independent radon survey conducted in homes during years 2022–2023. In this study, 79 rooms were monitored throughout the year in four cycles based on 3 month indoor radon measurements. The preliminary results show a good agreement between measured and calculated annual mean RAC.

To gain a deeper understanding of the conditions at decommissioned uranium mines, on-site monitoring of environmental radioactivity was conducted at a decommissioned uranium mine in southern China. The results showed that the average surface γ-ray dose rate in the mining area and surrounding regions ranged from 83.2 to 286.6 nGy h^–1, and the average concentration of radon and its progeny in the air ranged from 23.1 to 66.5 Bq m^–3 and 30.3 to 112.4 nJ m^–3, respectively, which are below the national regulatory limits of China. After remediation, the uranium mine did not cause radioactive pollution to spread into the surrounding environment, indicating the effectiveness of remediation efforts over time.