Upgrade of the Data Acquisition and Control System of Microwave Reflectometry on the Experimental Advanced Superconducting Tokamak

The reflectometry system on experimental advanced superconducting tokamak (EAST) is undergoing an upgrade for more comprehensive measurement of plasma density profile and fluctuation. The data acquisition and control system (DACS) has been redeveloped to satisfy the upgraded requirements. The profile reflectometry works in 30–110 GHz (X-mode) and 40–90 GHz (O-mode), when the fluctuation reflectometry operates at 20 fixed frequency points in 50–110 GHz (X-mode) and 20–60 GHz (O-mode). The PXIe-based DACS includes two 8-channel 14-bit 250 MSPS digitizers and ten 8-channel 12-bit 60 MSPS digitizers. A self-developed five-channel 250 MSPS arbitrary waveform generator (AWG) is used to control voltage control oscillators for frequency sweeping. A trigger and clock manager and a timing module receive the trigger and clock signal from the central controller and synchronize all the digitizers and the AWG. The total data rate from digitizers is 2515 MB/s. The data from digitizers is streamed to a disk array (RAID 0) with the data throughput capacity of 3000 MB/s. Meanwhile, the selected data are transported to an FPGA-based real-time data processing module, which utilize a pretrained neural network to calculate the plasma density profile. Now, the new reflectometry is being installed on EAST, and its performance is tested preliminarily in the 2018 experimental campaign.