The development of segmented electrode thin-filmparallel plate avalanche counter (PPAC)

In order to improve the counting rate and position resolution of the Parallel Plate Avalanche Counter (PPAC) within the Compact Spectrometer for Heavy Ion Experiment, a new strip film-structured PPAC has been developed. The developped PPAC detector consists of three layers of film electrodes. The upper and lower layers which serve as the anodes are comprised of self-developed strip film electrodes, oriented perpendicularly to each other. The middle layer utilizes double-sided aluminized Mylar film as the cathode. There is a 3 mm gap between each layer, and the detector has an effective area of 76mm x 76 mm. Operating in a low-pressure environment with isobutane gas as the working medium, the performance of the PPAC has been measured using a 5.486MeV alpha radiation source. The measurement results indicate that the overall position resolution of the PPAC attains approximately 380 mu m, and the position resolution improves to 300 mu mwhen using slit width correction. Finally, the Monte Carlo simulation has been performed to simulate the distribution of electrons generated by the detector's ionization under the same conditions on the anode readout strip. The simulation results closely matches the observed multiplicity of hit anode readout strips in measurement.