A Method for Preparing A Large Sized, Uniform and Stable Built-up Film of 109Cd Icosanoate as A Radioactive Source by Utilization of an Extremely Small Amount of Substrate Solution

Abstract

A stable radioactive source in vacuo was obtained by a modified horizontal lifting method of Langmuir-Blodgett (L/B) film. In spite of the slight consumption of the substrate solution (only 2–2.5 ml) for preparing a 15 mm×25 mm sized L/B film containing four molecular layers of ¹⁰⁹Cd icosanoate, the deposition of the film was complete. The reliability of the deposited films by this method was confirmed by their radioactivities, deposition ratios and autoradiographs. The condition to obtain a larger sized homogeneous L/B film (20–25 mm×102 mm) was also examined. Two or four molecular layers of nonradioactive Cd icosanote deposited on the L/B film of ¹⁰⁹Cd icosanoate did not influence the intensity of the γ-ray of 88.0 KeV. Concequently, it is possible to obtain the high radioactive source by the deposition of the multilayers of ¹⁰⁹Cd icosanoate. Spectra of L₂ and L₃ conversion electrons from the ¹⁰⁹Cd in its built-up film were also determined. In conclusion, the present depositing method for the L/B film is excellent for the manufacturing the radioactive source and thought to be also applicable for the deposition of other valuable materials.