Construction and performance test of prototype parallel plate avalanche counters at RAON

Two prototype position sensitive parallel plate avalanche counters (PPACs) have been fabricated at the Rare Isotope Science Project (RISP). Both detectors have active areas of 10 × 10 cm 2 and utilize a stripped electrode structure, together with a delay line readout, to extract position information. Testing was conducted with an 241 Am α source, and 2-dimensional position information was obtained. A position resolution of 0.55 mm full width at half maximum (FWHM), together with a position linearity of ±55 μm over a 67-mm detection range, were measured. A time resolution of 450 ps (FWHM) was also measured.