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| Format: | Artículo científico |
| Language: | en |
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Sociedade Brasileira de Física
2004
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| Online Access: | https://www.redalyc.org/articulo.oa?id=46434537 |
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Table of Contents:
- Monte Carlo Simulation of Activity Measurements by Means of 4¼¯ ¡ ° Coincidence System Mauro S. Dias Marina F. Koskinas Mauro N. Takeda Física, Astronomía y Matemáticas The methodology for simulating all detection processes in a 4¼¯ ¡ ° coincidence system by means of theMonte Carlo technique is described. The goal is to predict the behavior of the observed activity as a functionof the 4¼¯ detector efficiency. In this approach, the information contained in the decay scheme is used fordetermining the contribution of all radiations emitted by the selected radionuclide, to the measured spectra byeach detector. This simulation yields the shape of the coincidence spectrum, allowing the choice of suitablegamma-ray windows for which the activity can be obtained with maximum accuracy. The simulation canpredict a detailed description of the extrapolation curve, mainly in the region where the 4¼¯ detector efficiencyapproaches 100%, which is experimentally unreachable due to self absorption of low energy electrons in theradioactive source substrate. The theoretical work is being developed with MCNP Monte Carlo code, applied toa gas-flow proportional counter of 4¼ geometry, coupled to a pair of NaI(Tl) crystals. The calculated efficienciesare compared to experimental results. The extrapolation curve can be obtained by means of another Monte Carloalgorithm, being developed in the present work, to take into account fundamental characteristics of a complexdecay scheme, including different types of radiation and transitions. The present paper shows preliminarycalculated values obtained by the simulation and compared to predicted analytical values for a simple decayscheme. 2004 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46434537 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.3A Vol.34