A Simple Flattener for holding Filter Papers on Planchettes for Radioactive Counting

Abstract

THE use of a ‘Millipore’ chimney and filter paper provides a convenient means of collecting radioactive material for measurement of its activity. A major disadvantage of this system arises from the curling of these papers by the precipitated materials and the allied difficulties of fitting them in the planchette. The use of doubly gummed ‘Scotch’ tape provides only a partial solution to this problem, and if the material on the filter paper is to be analysed chemically afterwards, the tape adhesive may interfere. The use of liquid adhesives and, in the case of ‘Millipore’ filters, of solvents also does not solve this problem. The amount of collected material is limited by the point at which the precipitate will flake and not hold to the paper. Recently we devised a simple spring mechanism to hold the paper in the carriers.