Self-supported PEDT/PVC conducting membranes for 4πβ sources preparation

Gold-coated membranes stretched on stainless steel rings are generally used for the preparation of high quality 4πβ counting sources. We propose an alternative method for the preparation of such sources by the use of a low-Z composite conducting polymer; [poly(3,4-ethylene dioxythiophene)/poly(vinylchloride)] (PEDT/PVC). A solution containing an EDT monomer (3,4-ethylene dioxythiophene), an oxidizing agent [Fe(CH3-phi-SO3)3], PVC and tetrahydrofuran as solvent is spin-coated onto a glass substrate. After coating, the membrane is dried, removed and transferred to the surface of a water bath before being deposited on a stainless steel ring. This procedure takes little time in contrast to other methods. PEDT/PVC has a lower electrical conductivity than PEDT alone but the PVC provides the required tensile strength for the membrane self-support. Performances of usually used preparation techniques are compared. Parameters like β detection efficiency for 60Co, peak to valley ratio for 109Cd and aging are also discussed