RESUMEN
Radiation based gauges have been widely utilized as a nondestructive and robust tool for measuring the thickness of metal sheets in industry. The typical radiation thickness meter can just work accurately when the composition of the material is fixed during the measurement process. In conditions that material composition may differ substantially from the nominal composition, such as manufacturing rolled metals factories, the thickness measurements would be along with errors. The purpose of the present research is resolving the problem of measuring the thickness of metal sheets with various alloys. The aluminum is investigated in this work as a case study but the procedure can be applied for other types of metals. As the first step, the performance of various arrangements of two main detection techniques, named dual energy and dual modality, were investigated using MCNPX code to obtain optimum technique and arrangement. The simulation results indicated that a binary combination of 241Am-60Co isotopes as the source and one transmission detector in dual energy technique is the most appropriate choice. After then, an experimental setup based on the obtained optimal technique from simulation investigations was established. The aluminum sheets with 4 alloy types of 1050, 3105, 5052 and 6061 and thicknesses in the range of 0.2-4â¯cm with a step of 0.2â¯cm were tested and the obtained data were implemented for testing and training the artificial neural network (ANN). The proposed methodology could predict the thickness of aluminum sheet independent of its alloy type with an error of less than 0.04â¯cm in experiments.
RESUMEN
In this research gas sealed Multi-Wire Proportional Counter (MWPC) including blades between anode wires and beta particles of (90)Sr with 196keV mean energy were considered. Ten different gases such as Noble gases mixtures with methane and several other pure gases were studied. In this type of detector, by using Garfield and Maxwell codes and for each of the gases, variation of different parameters such as first Townsend, electron attachment coefficients with variable electric field and their effects on pulse height or collected charge and in turn on Signal to Noise Ratio (SNR) were studied. Also the effect of anode voltage and its diameter and the pressure of gas on the pulse height were studied. Results show that Garfield and Maxwell codes can be used to study and improve the design of other gaseous detectors.
RESUMEN
In this work, exchange radioiodination of metaiodobenzylguanidine (MIBG) was carried out at optimum conditions that facilitates the production of [(131) I]MIBG both quickly and efficiently. The radiochemical purity and yield of the labeled product are typically as high as 99% and 90% for diagnostic dose and 95% and 80% for therapeutic dose, respectively. Stability studies show that labeled material at the room temperature met the demand of the clinical application. This labeling procedure will be used in the routine production process of [(131) I]MIBG for diagnosis and treatment uses.
Asunto(s)
3-Yodobencilguanidina/síntesis química , Radiofármacos/síntesis química , 3-Yodobencilguanidina/química , Estabilidad de Medicamentos , Almacenaje de Medicamentos , Radiofármacos/químicaRESUMEN
(99m)Tc can be produced from (99)Mo/(99m)Tc gel generators. These gels are part of the generator and the (99)Mo/(99m)Tc gel generator performance is directly related with gel structure. In this work a series of zirconium molybdate gels have been synthesized and dried under different conditions and characterized using thermal analysis (TGA, DTA), SEM, XRD and porosity measurements. It is found that the water content of the gel determines the structure porosity which allows the diffusion of the (99m)TcO(4)(-) ions inside the gel and was directly connected with performance of the (99)Mo/(99m)Tc gel generators. Drying conditions of the gel is as an important factor that influence water content and physical-chemical properties of this gel and must be carefully studied to optimize the properties of the gel generators.