Ion transmission spectroscopy of pores filled with Au nanoparticles

Ion track membranes (ITM) are of long-term interest due to the high potential of applications in science and industry. However, the use of the membranes requires a detailed knowledge of (i) their structural parameters, i. e., the density and distribution of the ITM pores, the pore size (radius) and spatial shape, or (ii) the pore filling with other materials (demanding the knowledge of filling efficiency, filler confinement, or filler density). In this work, we studied the nuclear membranes prepared with pores of certain density and size and filled with Au nanoparticles. The analysis was carried out by Ion Transmission Spectroscopy (ITS). ITS is a nondestructive technique to determinate the spatial structure of (sub)micron inhomogeneities (pores, protrusions, etc.) in thin foils from the energy loss of even quasi-monoenergetic alpha particles (e.g., from a thin 241Am source) transmitted through the (empty or filled) pores. The reconstruction of the shape of the pores or pore fillings is performed by simulation of the transmission spectra using the MC code. The nuclear membranes were prepared by the irradiation of a thin polyethylene terephthalate with 157 MeV Xe+26 ions (with the fluence 10(6) cm(-2)) and the subsequent chemical etching in 9 M NaOH water solution at 50 degrees C for 40 min. The pores were filled with the Au nanoparticles (NPs) of a sub-micrometer size using the Pulse Laser Deposition (PLD), and studied by ITS. From the transmission spectra the shape of the pores filled (partially or fully) with Au NPs could be reconstructed. The ITM with pores filled with NPs were also analyzed by scanning electron microscopy (SEM). The results showed good agreement with the MC simulation of the ITS data.