Luminescence is the emission of light resulting from radiative transition of an atom from an excited state to a ground state. This radiative transition yields emission of photons and the luminescence is the general name which is used to classify &ldquo / cold emission&rdquo / other than the blackbody radiation. Spectroscopy involves the measurement of intensity of emitted, absorbed or scattered electromagnetic radiation as a function of wavelength. Thus, it is a valuable tool in the study of understanding the luminescence production mechanisms. Measurement of emission spectra gives information about the energy levels of transition and structure, geometry and composition of the sample. In this study, a versatile luminescence emission spectrometer was designed and developed with the main aim of measuring Photoluminescence (PL), Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) emission spectra of materials relevant for dosimetry. The spectrometer was constructed around a Littrow type monochromator by developing the necessary hardware, firmware and software. Wavelength calibration, measurement of spectral response and determination of resolution of the spectrometer were done using calibration lamps and a calibrated spectroradiometer. Finally the performance of the constructed spectrometer was tested by measuring the emission spectra of materials such as BeO, Al2O3 and CaF2 wherever possible the measured spectra were compared with the ones reported in the literature.

O óxido de alumínio foi um dos primeiros compostos investigados, com vista a detectar e medir a radiação por meio da termoluminescência (TL). Comumente referido como \"alumina\", o óxido de alumínio tem características interessantes para o desenvolvimento de materiais para a dosimetria. Seu número atômico efetivo é intermediário entre o do osso e do tecido mole do corpo. Pode ser transformado em material termoluminescente pela inserção de elementos químicos em sua estrutura cristalina. Além da TL, a alumina pode apresentar luminescência opticamente estimulada (OSL), fenômeno que também pode ser usado para determinar a dose de radiação. Neste estudo, dois métodos foram investigados para inserir íons metálicos na alumina. O primeiro método foi baseado na capacidade de adsorção da alumina e o segundo denominado método da coprecipitação foi baseado na formação simultânea de compostos insolúveis. As amostras obtidas por adsorção de íons Cu2+ e Mn2+ não mostraram resultados satisfatórios. No entanto, as pastilhas de óxido de alumínio impurificado com Tm3+ via coprecipitação mostraram sinais de TL e OSL. Foi verificado também que a alumina eletrofundida disponível comercialmente é um material que apresenta resposta TL e OSL. Este material que contém diversos íons metálicos em sua estrutura foi transformado em pastilhas por sinterização com vidro. As curvas da resposta TL em função da temperatura e da resposta TL e OSL em função da dose foram determinadas. Os resultados obtidos indicam que estudos mais aprofundados das pastilhas desenvolvidas podem melhorar suas características para que sejam aplicadas em dosimetria. / The aluminum oxide was one of the former compounds investigated with a view to detecting and measuring radiation by means of the thermoluminescence (TL). Commonly referred to as \"alumina\", aluminum oxide has interesting features for the development of materials for dosimetry. Its effective atomic number has an intermediate value between the bone and soft tissue of the body. It can be transformed into TL material by the insertion of chemical elements in its crystal structure. In addition to the TL, the alumina can provide optically stimulated luminescence (OSL) which can also be used to determine the radiation dose. In this study, two methods were investigated in order to insert metal ions in alumina. The first method was based on the adsorption capacity of alumina and the second named coprecipitation method was based on the simultaneous formation of insoluble compounds. The samples obtained by adsorption of Cu2+ and Mn2+ ions did not show satisfactory results. However, the aluminum oxide impurified with Tm3+ by coprecipitation showed TL and OSL signals. It was also found that the commercially available electrofused alumina is a material that exhibits TL and OSL. This material that contains various metal ions in its structure was made into pellets by sintering with glass. The TL response curves as a function of temperature and the TL and OSL responses as a function of the dose were determined. The obtained results indicate that further studies of the developed pellets can improve the characteristics in order to be applied in dosimetry.

O óxido de alumínio foi um dos primeiros compostos investigados, com vista a detectar e medir a radiação por meio da termoluminescência (TL). Comumente referido como \"alumina\", o óxido de alumínio tem características interessantes para o desenvolvimento de materiais para a dosimetria. Seu número atômico efetivo é intermediário entre o do osso e do tecido mole do corpo. Pode ser transformado em material termoluminescente pela inserção de elementos químicos em sua estrutura cristalina. Além da TL, a alumina pode apresentar luminescência opticamente estimulada (OSL), fenômeno que também pode ser usado para determinar a dose de radiação. Neste estudo, dois métodos foram investigados para inserir íons metálicos na alumina. O primeiro método foi baseado na capacidade de adsorção da alumina e o segundo denominado método da coprecipitação foi baseado na formação simultânea de compostos insolúveis. As amostras obtidas por adsorção de íons Cu2+ e Mn2+ não mostraram resultados satisfatórios. No entanto, as pastilhas de óxido de alumínio impurificado com Tm3+ via coprecipitação mostraram sinais de TL e OSL. Foi verificado também que a alumina eletrofundida disponível comercialmente é um material que apresenta resposta TL e OSL. Este material que contém diversos íons metálicos em sua estrutura foi transformado em pastilhas por sinterização com vidro. As curvas da resposta TL em função da temperatura e da resposta TL e OSL em função da dose foram determinadas. Os resultados obtidos indicam que estudos mais aprofundados das pastilhas desenvolvidas podem melhorar suas características para que sejam aplicadas em dosimetria. / The aluminum oxide was one of the former compounds investigated with a view to detecting and measuring radiation by means of the thermoluminescence (TL). Commonly referred to as \"alumina\", aluminum oxide has interesting features for the development of materials for dosimetry. Its effective atomic number has an intermediate value between the bone and soft tissue of the body. It can be transformed into TL material by the insertion of chemical elements in its crystal structure. In addition to the TL, the alumina can provide optically stimulated luminescence (OSL) which can also be used to determine the radiation dose. In this study, two methods were investigated in order to insert metal ions in alumina. The first method was based on the adsorption capacity of alumina and the second named coprecipitation method was based on the simultaneous formation of insoluble compounds. The samples obtained by adsorption of Cu2+ and Mn2+ ions did not show satisfactory results. However, the aluminum oxide impurified with Tm3+ by coprecipitation showed TL and OSL signals. It was also found that the commercially available electrofused alumina is a material that exhibits TL and OSL. This material that contains various metal ions in its structure was made into pellets by sintering with glass. The TL response curves as a function of temperature and the TL and OSL responses as a function of the dose were determined. The obtained results indicate that further studies of the developed pellets can improve the characteristics in order to be applied in dosimetry.

Optically Stimulated Luminescence (OSL) is the luminescence emitted from a previously irradiated insulator (or a wide band gap semiconductor) upon exposure to light. The OSL signal intensity is a function of the radiation dose absorbed by the sample and thus can be used as the basis of a radiation dosimetry method. In the literature, OSL studies on natural fluorites are rather limited. In order to promote the material for radiation dosimetry, OSL properties of natural fluorites of different origin were examined in this study. For this purpose, dose-response, reproducibility, thermal stability and fading of the OSL signals were analyzed. In order to find a relation between OSL and TL signals, TL signals and the effect of OSL measurements on TL signals were examined. Thermal activation energies of the light sensitive TL peaks and the OSL signals were also calculated using different methods and the results were compared. Also, absence of the thermal quenching was shown. Finally, TR-OSL signals were measured to have an opinion about the recombination centers. As a result of these studies, it is possible to conclude that natural fluorites show promising features to be used as an environmental dosimeter with regard to a suitable OSL signal, range of linearity, repeatability in response, as well as being readily available at a low cost.

第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第2部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall