Investigation of initial stage of chemical etching of ion tracks in polycarbonate

N. Sertova (1) , E. Balanzat (1) , M. Toulemonde (1) , C. Trautmann (2)

1 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique
2 GSI - Helmholtz zentrum für Schwerionenforschung GmbH

Chemical track etching experiments were carried out on thin polycarbonate films irradiated with Ca and Pb ions of energy ~5 MeV/u. Pore growth and corresponding etching rates were investigated for various fluences between 2x10^8 and 7x10^9 ions/cm-2 by means of infrared spectroscopy, weight measurements. From such an experimental behavior it is calculated that radial chemical etching rate (Vr), surrounding the track core, could reach value that is one order of magnitude larger than the bulk etch rate (Vb). Vr decreases when increasing the pore size and is equal to Vb only at large distance from the track axis. At larger fluence and near the core size, Vr reaches nearly immediately Vb. This latter effect could be ascribed to overlapping of the damaged halo zone surrounding individual track. On the basis of previous models developed for track etching, a smooth decrease of the radial etching velocity near the core track is introduced to account for the behavior of the loss of weight versus time appearing at low fluence. At larger fluence, the quadratic evolution of the loss of weight is described by a sharp transition of the radial etching velocity from Vt to Vb at the border of the latent track. This simple model cannot describe the evolution of the etching procedure for material irradiated at fluence of 7x10^9 ions/cm2. Deduced from the value of Vt, the use of the loss of weight measurement allows to follow the etching procedure before the break through of the pore.

Mots clés: polycarbonate; ion tracks; chemical etching; fluence; loss of matter; infrared spectroscopy

Domaines: Agrégats Moléculaires et Atomiques [physics.atm-clus]

N. Sertova, E. Balanzat, M. Toulemonde, C. Trautmann. Investigation of initial stage of chemical etching of ion tracks in polycarbonate. The Seventh International Symposium on Swift Heavy Ions in Matter, Jun 2008, Lyon, France. ⟨hal-00219753⟩