Time resolving bent crystal spectrometer for tokamak plasma diagnostics

A high-throughput high-resolution curved crystal spectrometer for measurements in the soft X-ray range on fusion magnetic devices is described. The spectrometer uses a large useful area (8 × 5 cm²) quartz lamina bent at a curvature radius 385 cm long as the dispersing element. The detector is a one-dimensional space resolving multiwire proportional counter. The spectral resolving power is R = 18 000, permitting to obtain adequate ion temperature measurements, down to 700 eV, from the Doppler broadening of resonance lines of highly ionized metallic impurities.