RESUMO
A neutron irradiator has been assembled at IPEN facilities to perform qualitative-quantitative analysis of many materials using thermal and fast neutrons outside the nuclear reactor premises. To establish the prototype specifications, the neutron flux distribution and the absorbed dose rates were calculated using the MCNP computer code. These theoretical predictions then allow one to discuss the optimum irradiator design and its performance.
Assuntos
Amerício , Berílio , Terapia por Captura de Nêutron de Boro/métodos , Nêutrons , Radiometria/instrumentação , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Marcação por Isótopo/instrumentação , Marcação por Isótopo/métodos , Modelos Químicos , Doses de Radiação , Compostos Radiofarmacêuticos/análise , Compostos Radiofarmacêuticos/síntese química , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The level structure of 149Pm has been investigated by studying the gamma rays emitted following the beta(-) decay of 149Nd (T(1/2)=1.7h). The singles and the gammagamma coincidence spectra were taken using HPGe detectors with high energy resolution. The energy and relative intensities of 198 gamma rays have been determined, 45 for the first time and several multiplets were resolved using bidimensional data analysis. A decay scheme with 51 levels has been proposed. This includes 6 new levels, at 1407, 1368, 1364, 1329, 1293 and 1181keV. The present results permitted assignments of spin and parity for a number of these levels.
RESUMO
The gamma-ray spectrum of 139La following the beta- decay of 139Ba has been studied using both singles and gammagamma coincidence spectroscopy techniques. The energies and intensities of 30 gamma-transitions have been determined, which include three new transitions placed in the level scheme. Two new levels at 1524.6 and 1900.3 keV excitation energies are proposed and a number of gamma-transitions have been confirmed. On the basis of these results a precise decay scheme is proposed.
