A versatile large area parallel plate avalanche counter (PPAC) for the broad-range magnetic spectrographs

A versatile parallel plate avalanche counter has been developed for the identification of nuclear reaction products. A novel construction of its transmission electrodes with an active area of 354 x 22 mm2 is presented in detail. The counter under test was filled with n-heptane vapour at a pressure of 18 Torr. Its timing properties were investigated with the use of time-of-flight technique employing 1.6-4 MeV α-particles and a solid state detector. The time resolution was 380 ps (fwhm). Besides, the electric characteristics of the counter, energy resolution in the range of low-energy α-particles, inhomogeneity of the detector geometry, and non-linearity of the internal time delay along the electrodes are discussed. (author)