Development of the HCN heterodyne collective scattering system on J-TEXT

A heterodyne collective scattering system has been designed and developed to investigate the turbulent transport of core plasma on J-TEXT.A dual-HCN laser which consists of two separately pumped HCN gas lasers at 337μm has been developed as the laser source of the scattering system.The intermediate frequency(IF)is~1 MHz when there is a 4μm cavity length difference and capable to maintain stability more than 5 h without manual operation.Detection channels at three different angles(2≤k_(⊥)≤12 cm^(-1))have been installed with Schottky barrier diode mixers of 893 GHz.The sampling frequency of the acquisition system is6 MHz to observe low-frequency density fluctuations.Initial experimental results have been detected and more results can be expected in future experiments.