Fast data acquisition system based on digital oscilloscopes for fluctuation measurements in a long pulse JT-60U tokamak plasma

We have developed a new data acquisition (DAQ) system with fast sampling rate for fluctuation measurements in a long pulse JT-60U tokamak plasma. This system is based on a powerful digital oscilloscope, which has a large acquisition memory up to 50 Mwords/ch, 1 MHz sampling rate and 16 bits high resolution AD convertors. The system is composed of plural digital oscilloscopes and mass storages. On this system, most of data acquisition processes are executed at each digital oscilloscope. This feature of the system leads to an advantage that the processing loads are distributed among the digital oscilloscopes. This system has been successfully employed for measurements of various fluctuations obtained through magnetic probes, beam emission spectroscopy and so on. The size of the acquired data using this system has reached up to 10 GB/shot so far. It has demonstrated that this system is very powerful for data acquisition of multi-channeled signals with high time resolution in a long pulse plasma.