The electrochemical etching of fission fragment tracks in tuffak polycarbonate

A detailed and systematic study on the ekectrochemical etching (ECE) characteristics of fission fragment tracks in the new Tuffak polycarbonate has been made. These studies have enabled us to determine optimum conditions for the unambiguous detection and identification of fission tracks without any interference from background tracks due to surface defects, neutron-induced recoils and alpha-particle tracks, emitted by radon and its decay products. The optimum conditions were found to be 20 min pre-chemical etching (PCE) with 6 M NaOH at 60°C; followed by 30 min of electrochemical etching at 20 kV cm^-1, 2 kHz, in a solution of 15% KOH, 40% ethyl alcohol, 45% water, at a temperature of 25°C. Under these conditions, the fission tracks develop into “trees” of size 25–30 μm, with a clearly visible tail. In some tracks a “double tree” was observed.