Projeto e construção de um amplificador para espectrometria Gama

Abstract

In this work we developed a low cost amplifier to be coupled to a sodium iodine detector for gamma spectrometry. The project consists of an amplifier - mounted on the printed circuit board and aluminum armor- with the following characteristics: power source with symmetric 12 V; NOTCH filter to eliminate noise signals of 60 Hz; BNC connectors for input and measurement of signals generated by radiation; setting voltage gain and offset correction voltage via external potentiometer in the non inverting input of operational amplifier. In order to test the efficiency of the amplifier, tests were made voltage gain and offset adjustments by PROTEUS simulation program, and determined the frequency response as a function of voltage gain using a function generator and an oscilloscope. Was calculated using three measurements of the uncertainty of the input voltage and output device in question, with a range of 0.8 V to 2 V with digital multimeter. Finally, for validation of the project, compared the operation of the amplifier designed with a model marketed, the amplifier CANBERRA of 2012. The tests were performed with the radiation sources of cesium-137, americium-241, barium-133 and europium-152 using a sodium iodide detector (NaI (Tl)). The results showed that the amplifier can be used in developing other types of detectors such as proportional and gas. It was found, and also that the spectra obtained with the amplifier is shown better results than those obtained with the amplifier business.