The required rejection ratio of the stray light in a CTS, respect to the launching power is investigated, for obtaining useful signal-to-noise ratio. This problem is faced considering the central gyrotron frequency f0, as well as the in-band stray light raising from the spurious mode of the gyrotron and amplified cyclotron emission (the so-called gyrotron noise), falling into the scattered light spectrum. The statistical nature of the gyrotron noise in the scattering band is important because the required decoupling is obtained using the S/N formula where the fluctuation of the plasma radiation and the gyrotron noise fluctuation appears. It turns out that the total decoupling required at f0is of the order of or greater than 80 dB, while in the scattering band could be less than 40 dB. © 1995 American Institute of Physics.
All Science Journal Classification (ASJC) codes
Orsitto, F., & Tartari, U. (1995). Antenna decoupling requirements in a gyrotron collective Thomson scattering diagnostic (CTS). Review of Scientific Instruments, 66(2), 1159 - 1162. https://doi.org/10.1063/1.1145997