A 32/64-channel Charge eXchange Recombination Spectroscopy (CXRS) and a 7-channel motional Stark effect (MSE) polarimeter have been developed on the HL-2A tokamak. To extract the maximum time resolution of the system, the incidence fibers of the spectrometer are pitch-controlled; and the double-slit fiber bundle can increase the spatial channels with one charge-coupled device detector. The ion temperature and plasma rotation with time and spatial resolutions up to 5 ms and 1 cm are obtained. Sawtooth oscillation, transition from intermediate phase (I phase) to high confinement mode (H mode) can be clearly observed by the CXRS. The spectrometer can be utilized as the main component of the MSE polarimeter, which can effectively overcome the weak Stark effect. The pitch angles of magnetic field are obtained for 7 spatial points covering 24 cm along major radius with time resolution of 40 ms.
Intrinsic ˇ-Ga 2 O 3 and Zn-doped ˇ-Ga 2 O 3 films were prepared using RF magnetron sputtering. The effects of the Zn doping and thermal annealing on the structural and optical properties are investigated. In comparison with the intrinsic ˇ-Ga 2 O 3 films, the microstructure, optical transmittance, optical absorption, optical energy gap, and photoluminescence of Zn-doped ˇ-Ga 2 O 3 films change significantly. The post-annealed ˇ-Ga 2 O 3 films are polycrystalline. After Zn doping, the crystallization deteriorates, the optical band gap shrinks, the transmittance decreases and the UV, blue, and green emission bands are enhanced.
The structural deformations caused by environmental changes in temperature, vibration, and other factors are harmful to the stability of high precision measurement equipment. The stability and optimal design method of a 2D optoelectronic angle sensor have been investigated in this study. The drift caused by structural deformations of the angle sensor has been studied and a drift error model has been achieved. Key components sensitive to thermal and vibrational effects were identified by error sensitivity analysis and simulation. The mounts of key components were analyzed using finite element analysis software and optimized based on the concept of symmetric structures. Stability experiments for the original and optimized angle sensors have been carried out for contrast. As a result, the stability of the optimized angle sensor has been improved by more than 63%. It is verified that the modeling and optimal design method is effective and low-cost, which can also be applied to improve the stability of other sensors with much more complex principles and structures.
A gas puff imaging (GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak. The principle and experimental setup of GPI are described. GPI is applied to investigate blobs in the edge and scrape-off layer. Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions (PDFs), skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes. Besides, the track of blob motions is recorded by time sequence of individual frames. The characteristics of the original images and the relatively high-frequency (>10 kHz)/ low-frequency (1-10 kHz) component images are illustrated. The observation of the blob's structures and high-speed motions proves the success and high performance of the GPI diagnostic.
Laser-induced breakdown spectroscopy (LIBS) quantitative measurement is harassed by the variability of collected spectra, and the matrix effect of sample is the main reason. The surface geometric morphology of the...
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