A divertor Thomson scattering (TS) system being developed for ITER has incorporated proven solutions from currently available TS systems. On the other hand any ITER diagnostic has to operate in a hostile environment and very restricted access geometry. Therefore the operation in an environment of intensive stray light, plasma background radiation, the necessity meet the requirement using only a 20 mm gap between divertor cassettes for plasma diagnosis as well as to measure plasma temperatures as low as 1 eV severely constrain the divertor TS diagnostic design. The challenging solutions of this novel diagnostic system which has to ensure its steady performance and also the operability and maintenance are the focus of this report. One of the most demanding parts of the in-vessel diagnostic equipment development is the design assessment using different engineering analyses. The task definition and first results of thermal, e/m and seismic analyses are provided. The process of further improving of the design involves identification of

We demonstrate a diode-pumped master oscillator power amplifier Nd:YAG 1064 nm laser with sub-joule-level output energy of 0.43 J, high pulse repetition rate of 200 Hz, and short pulse duration of 100 ps. The 5 mJ master oscillator consisted of a 100 nJ/100 ps Nd:YVO microchip laser and end-pumped Nd:YAG regenerative amplifier. The two-pass output amplifier was based on two ∅10×140  mm Nd:YAG laser rods. We apply an adaptive compensator with an analyzer based on an astigmatic optical system and a quadrant photodiode to compensate for low-order wave-front non-stationary thermal distortions in a high-energy laser amplifier. The adaptive compensator demonstrates high sensitivity to curvature changes of λ/100, and it provides output beam divergence near 1.5×DL in 100 ps 0.43  J×200  Hz of operation mode.

No abstract

No abstract

No abstract