Preparation of thin plastic conductive foils for use in a position-sensitive micro-channel plate detector system

For the detection of recoiling nuclei at the focal plane of the Argonne Fragment Mass Analyzer (FMA), a device employing position-sensitive micro-channel plates (MCP) was constructed. Heavy ions, when traversing a thin foil within the detector, produce secondary electrons, which are deflected by an electrostatic mirror onto the micro-channel plates where they are multiplied and counted. This thin foil serves the dual roles of producing these electrons as well as providing an electrode for the electric field. A further constraint placed upon the foil is that it should not interact detrimentally with the heavy-ion beam, and be strong enough to withstand the force produced by the potential gradient of the electric field. Preparation techniques for the thin metallized plastic films needed for this detector system are described and their performance is evaluated.