Applicability of the polyimide films as a new SSNTD material

Threshold of etchable track registration in Polyimide films, KAPTON, has been examined through both chemical etching and a series of studies on latent track size using FT-TR spectrometry. The films exposed to protons, C, Ne, Fe and Xe ions at incident energies less than 6 MeV/n. The chemical etching was made in sodium hypochlorite solution with about 13.5% initial concentration of free chlorine at temperature of 55 degree of C. The etch pits are found only on the films exposed to Fe and Xe ions, indicating significant difference on the etch pit size between them. Threshold level is inferred to be around 3,200 keV/μm. On the other hand, the radiation chemical yields and the corresponding track core size for the loss of diphenylethers, C=O and C-N-C bonds composing imide bonds, have been evaluated by FT-IR spectrometry under the irradiations by Ne, Fe and Xe ions at energies below 6 MeV/n. The effective track core radius at 3,200 keV/μm is more than 1.2 nm that is more than 2.4 nm in diameter, which is larger than the length between the adjacent diphenylether bonds in the KAPTON chains. (author)