Study of a 4?(PS)?-? Coincidence System for Absolute Radionuclide Activity Measurement Using Plastic Scintillators / Estudo de um sistema de coincidências 4-pi-beta-gama para a medida absoluta de atividade de radionuclídeos empregando cintiladores plásticos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The present work was intended to study a coincidence system 4?(PS)?-? for absolute activity measurement using plastic scintillators in 4? geometry. Along with experiments on the coincidence system, simulations were also performed applying the Monte Carlo Method, by means of codes PENELOPE and ESQUEMA. These simulations were performed in order to calculate the extrapolation curve of the coincidence system 4?(PS)?-? and compare it to experimental data. A new geometry was proposed to the coincidence system adding up a second photomultiplier tube to the previous system for improving light collection from the plastic scintillator, as this system presented limitations in the minimum detected energy due to the presence of electronic noise and low gain. The results show that an improvement in the signal-to-noise ratio was obtained, as well as in the minimum detected energy. Moreover, there was an increase in the detection efficiency. With these modifications, it is now possible to calibrate radionuclides which emit low energy electrons or X-rays, increasing the number of radionuclides that can be standardized with this type of system.

ASSUNTO(S)

cintilador plástico coincidencia coincidencia monte carlo monte carlo atividade. atividade. cintilador plástico

ACESSO AO ARTIGO

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