Thomson scattering diagnostic system for the XuanLong-50 experiment
H. Y. Li, S. J. Li, Q. F. Xie, J. H. Liu, Ruixin Bai, Ran Tao, Xulei Lun, N. Li, X. K. Bo, C. Q. Liu, L. Han, B. H. Deng
Abstract
A 15-point Thomson scattering diagnostic system is developed for ENN’s spherical torus experiment XuanLong-50 (EXL-50). A BeamTech laser with 3 J/pulse (1064 nm wavelength) at 50 Hz repetition rate is chosen for measurements during EXL-50 plasma operations. To enable measurements at low density (∼0.5 × 1018 m−3) plasma operations, the opto-mechanical subsystems are carefully designed to maximize the collection and transmission of the scattered light and to minimize the stray light level. In addition, the high bandwidth trans-impedance amplifiers and segmented high speed waveform digitizers allow for the application of muti-pulse averaging to further improve the signal-to-noise ratio. Details of the diagnostic system are described and initial experimental results are presented.