关键词: 电子回旋辐射, 外差式辐射计, 扫频, 对数检波器, 电子温度测量

Abstract: In order to measure the electron temperature profile on HL-2M, a sweeping frequency electron 
cyclotron emission (SECE) system is developed. The system can measure electron temperature of plasma with the 
center toroidal field of 1.4~2.2T. The radial spatial resolution is 2.5cm and the temporal resolution is 1ms by using 
the method of frequency-swept heterodyne radiometer technique. The quasi-optical system at the front of the 
receiver is equipped with two-stage metal mirrors. The minimum diameter of a poloidal spot that the system can 
receive is 1.5cm (wave number k_θ<4.2rad·cm^-1) The system covers 33~110GHz bandwidth with 3 voltage 
controlled oscillators (VCO) used as the source of local oscillators (LO), and the intermediate frequency (IF) 
signal is output by mixing in double sidebands. The backend uses high-performance logarithm detector to 
demodulate IF signal for the first time, which can detect the weak signal of -70dBm. The dynamic range of the 
input power reaches 45 dB. During HL-2M experiments, the signals generated by runaway electrons and electron 
cyclotron emission (ECE) in plasma were measured successfully. 

Key words: Electron cyclotron emission, Heterodyne radiometer, Sweeping frequency, Logarithmic detector; 
Electron temperature measurement