High-n Rydberg transition spectroscopy for heavy impurity transport studies in W7-X (invited).

Here, we present a novel spectroscopy approach to investigate impurity transport by analyzing line-radiation following high-n Rydberg transitions. While high-n Rydberg states of impurity ions are unlikely to be populated via impact excitation, they can be accessed by charge exchange (CX) reactions along the neutral beams in high-temperature plasmas. Hence, localized radiation of highly ionized impurities, free of passive contributions, can be observed at multiple wavelengths in the visible range.

High speed fast-ion D-alpha spectrometer for the NSTX-U tokamak.

Here, we present the design and first calibration results of a new single-channel Fast-Ion D-Alpha (FIDA) spectrometer to be employed at the National Spherical Torus Experiment Upgrade (NSTX-U). The Czerny-Turner-type spectrometer uses a custom-designed aspherical lens setup instead of mirrors and achieves excellent spectral resolution, with high photon throughput through a round-to-linear fiber bundle, and camera frame rates around 8.4 kHz.

Accurate and sensitive mutational signature analysis with MuSiCal.

Mutational signature analysis is a recent computational approach for interpreting somatic mutations in the genome. Its application to cancer data has enhanced our understanding of mutational forces driving tumorigenesis and demonstrated its potential to inform prognosis and treatment decisions. However, methodological challenges remain for discovering new signatures and assigning proper weights to existing signatures, thereby hindering broader clinical applications.

Design of a new charge exchange recombination spectroscopy diagnostic for impurity transport experiments at Wendelstein 7-X.

In this study, we present the design of a new charge exchange recombination spectroscopy (CXRS) system for Wendelstein 7-X (W7-X), which aims at measuring line radiation from highly ionized iron impurities after laser blow off injections over transport timescales. New fiber bundles with a core diameter of 600 µm have been added to one of the existing optical systems at W7-X used for CXRS. The fibers direct collected light to five newly developed single channel high frame rate F/2.