Speaker
Description
Soft and hard x-ray diagnostics are foundational tools in high-temperature plasma and fusion research, enabling measurements of magnetohydrodynamic (MHD) stability, energy confinement, impurity transport, runaway electron dynamics, radiated power, plasma–wall interactions, and disruptions. To significantly expand diagnostic capability, a novel multi-energy hard x-ray camera has been developed and calibrated by DECTRIS and PPPL, and deployed at WEST (CEA, France). This system features independently adjustable energy thresholds for each “smart” pixel, enabling unprecedented mapping flexibility on a 2D sensor. The high quantum efficiency of highZ detectors extends x-ray studies of radiative plasmas up to photon energies of 10–50 keV for GaAs and 10–100
keV for CdTe. The use of versatile CdTe multi-energy systems provides a major improvement in throughput and signal-to-noise ratio, enabling adequate spatial and temporal resolution (Δr/a≈1–5% and Δt≈0.5–50 ms, depending on signal to noise ratio [SNR]). For future burning plasmas with electron temperatures of 10–30 keV, a multi-energy CdTe sensor can sample the energy dependence of the thermal continuum to measure (a) the electron temperature (Te) and (b) the plasma effective charge (Zeff). At higher photon energies (30–100 keV), several non-Maxwellian features can be resolved, including (c) interactions of fast electrons with tungsten plasma-facing components (PFCs), (d) inference of RF-driven currents, (e) anisotropic emission from fast RFdriven electrons, and (f) the time evolution of runaway electrons (RE). Finally, integration with real-time control paves the way for non-magnetic equilibrium reconstructions and fast-acting RE alarms, pointing to a broader diagnostic paradigm for future fusion devices.