Delay-line PPAC for high-energy light ions

We have developed a delay-line parallel-plate avalanche counter (PPAC) with high detection efficiency for high-energy light ions. A large signal-to-noise ratio was achieved by a newly designed pre-amplifier and the usage of C3F8 gas at a pressure of 30 Torr. The counter has been tested with beams of 90 A MeV 7Li at RIKEN, 340 A MeV 12C at GSI, and 254 A MeV 8B at GSI. We achieved high detection efficiencies (>95%) for all of these ions. Furthermore, we achieved reasonable position and timing resolutions.