A 4pi(LS)beta-gamma coincidence system using a TDCR apparatus in the beta-channel.

This article is an overview of the capabilities of a 4 pi(LS)beta-gamma coincidence counting system based on a liquid scintillation detector in the beta-channel. Equipped with a three-photomultiplier apparatus designed for the triple to double coincidence ratio (TDCR) method, the 4 pi(LS)beta-gamma coincidence system developed at LNHB combines the two techniques. The 4 pi(LS)beta-gamma counting setup records the different types of scintillation events between photomultipliers (double and triple coincidences) and the associated gamma-spectra according to a bi-dimensional configuration.

Freeze-drying applied to radioactive source preparation.

In the framework of R&D studies for the improvement of radioactive source efficiencies prepared on thin films for 4pibeta-gamma coincidence counting, a comparative study on two drying methods has been undertaken in our laboratory (BNM-Laboratoire National Henri Becquerel, France). The standard method of evaporation at atmospheric pressure and a method based on freeze-drying using commercial equipment are compared. The preliminary results of this study obtained with 65Zn sources are presented and a significant improvement of the detection efficiencies to the electron emission for freeze-dried sources is shown.