Uniform position-sensitivity verification of novel electrochemically-etched panorama mega-size polymer ion image detectors

Abstract

Recent novel applications of mega-size polycarbonate ion image detectors processed in mega-size electrochemical etching chambers have raised concerns on uniform position-sensitivity and consistency in ion energy responses of detectors with different effective areas. In this context, the uniform position-sensitivity, detection efficiency and track diameters of alpha particles over a broad energy range in detectors of different effective areas; i.e. small size (2 × 2 cm2), medium sizes (17 × 17 cm2) and (22.6 × 22.6 cm2), as well as large (33 × 33 cm2) were investigated in order to make them independent of the detector effective area. Alpha particles of 6 different energies from ∼0.3 to ∼3.0 MeV at a fluence of ∼1.0 × 104 alphas·cm−2 were studied applying 50 Hz – HV field conditions. As an example, 36 positions on 6 rows and 6 columns of a 33 × 33 cm2 detector were studied. By having the same efficiency and mean track diameter only at ∼0.8 MeV alpha energy in different detector effective areas under the conditions applied, it is concluded that: (1) position-sensitivity, efficiency and alpha energy responses are consistently uniform independent of the detector effective areas for particles with dE/dX)particle ≥ dE/dX)alpha at ∼0.8 MeV, but (2) a “voltage compensation factor” (Vc) commensurate with each detector effective area and type of particle should be applied for particles with dE/dX)particle ≤ dE/dX)alpha at ∼0.8 MeV for efficient, consistent and uniform ion detection.