CONSTRUCTION OF A 100-HZ-REPETITION-RATE 28-CHANNEL THOMSON SCATTERING SYSTEM FOR THE JIPPT-IIU TOKAMAK

An ASDEX-type Thomson scattering system (YAG Thomson) with an improved performance (100 Hz repetition rate and 1.5 cm spatial resolution) wa s designed and constructed for the JIPPT-IIU tokamak. Efforts were con centrated on realizing a large solid angle of collection optics (0.08 sr), high throughput of polychromators (>64%) and high quantum efficie ncy of detectors (80% at 900 nm), which, together, yield high-quality data even with a small laser energy (0.4 J) delivered by a 100-Hz-repe tition-rate Nd:YAG laser and with a short scattering length (1.0 cm). The compactness of the polychromators also contributes to achieving a high spatial resolution.