Liquid Scintillation Spectrometry Laboratory

This laboratory is designed to analyze non-environmental alpha and/or beta emitting tracers applied to research. This laboratory includes a spectrometer, QuantulusTM 1220, manufactured by PerkinElmer, which operates with an extremely low background due to the configuration of its two-detector system covered by a 200 mm lead wall and an anti-coincidence electronic circuit. The implementation of a pulse shape analyzer (PSA) allows the separation of counts generated by α and b radiation in the counting equipment. QuantulusTM achieves ultra-low background levels thanks to its two forms of shielding (passive and active). The passive shielding consists of an asymmetrical 650 kg lead block constructed from low residual activity lead. The internal cavity is lined with high purity copper that surrounds the photomultiplier tubes. A layer of cadmium, coated with copper, surrounds the sample and its two photomultiplier tubes ('S') to protect against neutrons. This (passive) shield is thickest at the top, where the cosmic ray flux is most intense. The active shield in QuantulusTM is in the form of a liquid scintillation anti-coincidence shield, which completely surrounds the sample PMTs within the lead shield. This active shield has an additional pair of PMT 'guard' detectors, which normally operate in anti-coincidence with the sample PMTs, thus rejecting the pulses produced by cosmic radiation.

Contato: 

Amenônia Maria Ferreira Pinto - amfp@cdtn.br - Tel.: +55 31 34399625