Imaging x-ray crystal spectrometer (XCS) arrays are being developed as a US-ITER activity for Doppler measurement of T-i and v profiles of impurities (W, Kr, and Fe) with similar to 7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a prototype instrument on Alcator C-Mod, uses a spherically bent crystal and 2D x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure Ti and both poloidal and toroidal rotation velocity profiles. The measurement of many spatial chords permits tomographic inversion for the inference of local parameters. The instrument design, predictions of performance, and results from C-Mod are presented.
- doppler measurement
- X-ray spectrometers
- X-ray imaging
Hill, K. W., Bitter, M., Delgado-Aparicio, L., Johnson, D., Feder, R., Beiersdorfer, P., ... Lee, S. G. (2010). Development of a spatially resolving x-ray crystal spectrometer for measurement of ion-temperature (T-i) and rotation-velocity (v) profiles in ITER. Review of Scientific Instruments, 81(10), 10E322. https://doi.org/10.1063/1.3492414