Charge response of polyethylene terephthalate polymers (PET) to light and heavy nuclei

A particular brand of common polymer film has been found to have a high detection threshold value of Z/β, when used as a solid state nuclear track detector to detect energetic ion beams. From the infra-red absorption spectrum the film was identified to be polyethylene terephthalate (PET). Elemental analysis indicated the chemical formula of the polymer to be (C5H4O2)n, which is also the same as that for PET. The charge response of this PET detector to light nuclei viz 16O-ions has been studied using 53.6 MeV 16O-ions from IUAC, New Delhi, India, using the air gap between the flange of the beam pipe and the detector as the energy degrader. The charge response for this PET detector has also been studied for heavy nuclei viz 238U using 11.1 MeV/n U-ion beam from GSI, Darmstadt, Germany, with aluminium foils of different thickness to degrade the incident energy to several values. The charge response parameter Vt/Vg has been plotted against the z/β of incident ions in the PET detector as part of a program to calibrate this detector so that it can be used to identify rare cosmic ray events