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HK: Hadronen und Kerne

HK 56: Postersitzung

HK 56.51: Poster

Wednesday, March 18, 1998, 17:00–19:00, Foyer

A liquid-scintillation detection system for low level α - spectroscopy in flowing organic solutions — •N. Wiehl, K. Eberhardt, J.V. Kratz, O. Kling, M. Mendel, A. Nähler, U. Tharun, and N. Trautmann — Institut für Kernchemie, Universität Mainz, D-55128 Mainz, Germany

A liquid-scintillation counting system for on-line studies of the chemical and nuclear properties of transactinide elements has been developed. The chemical separation of transactinide elements, produced in heavy ion reactions, is performed with continous liquid-liquid extraction using the centrifuge system SISAK 3 [1]. The very low production rates from a few atoms per hour down to a few atoms per day require a very efficient detection system for the α - emitting transactinide elements as liquid scintillation counting [2]. The elements of interest are extracted directly from the aqueous phase into an organic scintillator solution. The organic phase is then pumped through four detector cells arranged in series. With relatively large volume detector cells (7 ml) an energy resolution of 300 keV at 5 MeV was obtained. For β - and γ background suppression pulse-shape discrimination in combination with pile-up rejection has been applied. Details of the detection system and first experimental results will be presented.

[1] J.Alstad et al., J. Radioanal. Nucl. Chem. 189, 133 (1995)

[2] B.Wierczinski et al., Nucl. Instr. Meth. A 370, 532, (1996)