Overview on R&D and design activities for the ITER core charge exchange spectroscopy diagnostic system

Application of a grid numerical method to calculate state-selective cross sections for electron capture inBe4++H(1s)collisions

“…The diagnostics is based on the emission, usually in the visible spectrum (see [6]), of the excited ions, X (q−1)+ * . The application of the CXRS diagnostics requires the knowledge of state-resolved EC cross sections (1), which are in general difficult to measure, and, in particular, only theoretical data are available for collisions involving Be q+ ions.…”

Status of the R&D activities to the design of an ITER core CXRS diagnostic system

“…The impact of geometrical deviations as they can occur as a result of manufacturing inaccuracies is assessed in [21]: deviations in the order of a 1-2 mm do not modify frequencies or preloads by more than 2-3%. Such investigations give confidence that, if a simplified prototype can be built successfully, the concept of a frictionless fast shutter can be adapted to new optical designs which may be quite different from the baselines given in [22,23]. Note that the estimated lifetime of the pneumatic actuator amounts to >10 5 cycles on average for operating temperatures around 100 • C and pressure rise/decrease values from 0 to 5 bar within the given 0.7 s. …”

“…9. The arrangements (a) and (b), presented in [22] and [23] respectively, were dropped for practical reasons. The retractable tube, for instance, proves to be extremely hard to implement in view of the limited space behind the rear plate of the plug and the lack of possible coverage by remote handling.…”

A high etendue spectrometer suitable for core charge eXchange recombination spectroscopy on ITER

“…Therefore, in order to comply with the measurement requirements and compensate for those two effects, a high efficient optical system is required. A feasibility study for the ITER core CXRS system 1,3 pointed out that the spectrometer etendue should be at least 1mm 2 sr, to have a S/N of the order of 10. This value, in combination with the boundary conditions on the spectral wavelengths bands, resolutions, and transmission efficiencies, motivated a new dedicated design of such instrument.…”