Perspectives of CsI:Tl Crystals in g-Spectrometers

The article describes the problems of creating a scintillation spectrometer with a CsI:Tl crystal to replace spectrometers with NaI:Tl crystals which are widely used at nuclear power plants (NPPs) to monitor the activity of air, waste water and adjacent territories. The advantages of CsI:Tl-spectrometers are in the best energy resolution; much greater resistance to mechanical and electromagnetic influences due to the use of silicon photomultipliers (SiPM) instead of vacuum photomultiplier tubes (VPMT); much greater durability due to the very low hygroscopicity of the material. The strong mismatch between the emission spectrum of the crystal and the spectral sensitivity of the VPMT photocathodes, the relatively long decay time and the complex, multicomponent form of the light flash made spectrometers with CsI:Tl crystals not competitive. The paper describes the methods of constructing a spectrometer, which made it possible to realize the useful properties inherent in a crystal and to level its disadvantages. As a result of the cycle of research and development work, the Stark-02 intellectual detector has been designed and described. Typical relative energy resolution with crystals of volume 45 cm3 at an energy of 662 keV of the 137Cs source is better than 6.5% in the ambient temperature range Q = +10 ÷ +45 °C and not worse than 7.5% in the extended range Q = –25 ÷ +55 °C.

A new approach to process gamma scattering spectra for aluminum materials

In this study, we used Monte Carlo method to simulate each separate component of the gamma scattering spectrum. The gamma rays emitted from a 137Cs source, scatter on aluminum targets and recorded by a NaI(Tl) detector. Based on the distribution characteristics of each scattering component, we propose a new method to analyze scattered gamma spectra. This method was applied for simulated spectra to estimate the material thickness gives good results.

Degradation of 4-Chlorophenol by Gamma Radiation of 137Cs and X-rays

This paper presents results of radiolytic degradation of 4-chlorophenol in the presence of TiO2, Al2O3, y SiO2, using different radiation sources than 60Co, which is so common in this type of experiment. The radiation sources used were X-rays with energy of 100 keV and radiation from 137Cs (662 keV). After irradiation with a dose of 50 cGy X-ray and TiO2 obtained a degradation of about 5%, no degradation was obtained with 137Cs source and other oxides. This may be due to the fact that X-rays have a linear energy transfer (LET) greater value, and in the case of TiO2 present a crystalline structure, whereas the other two oxides are amorphous. Both characteristics result in better formation of a reactive species that allows the degradation of the compound.

Исследование спектров фотолюминесценции нанокристаллов AgInS-=SUB=-2-=/SUB=-/ZnS при воздействии γ-излучения

The effect of different doses of γ-radiation from a 137Cs source on photoluminescence of Ag-In-S nanocrystals covered with a shell of wider bandgap ZnS was investigated. The dynamics of changes in the nanocrystals photoluminescence depending on the dose of γ-radiation was shown. It was established that the AgInS2 / ZnS nanoparticles retain their photoluminescent properties and colloidal stability upon reaching the absorbed dose of 6 • 10^3 Gy (to water). Residual photoluminescence persisted when the absorbed dose reached 10^6 Gy. It was shown that AgInS2 / ZnS nanocrystals can be used in medical and biological studies in which increased resistance to gamma radiation is needed.

DENSITY CORRECTION FOR GEOPHYSICAL WELL LOGGING INSIDE DRILLING RODS

ABSTRACT. This paper brings the results of the application of a casing correction applied to density logging inside drill rods using a 137Cs source intended to iron ore exploration. A set of runs... RESUMO. Este trabalho traz os resultados da aplicação de uma correção para perfilagem geofísca no interior de haste de sondagem utilizando uma fonte de 137Cs na exploração...