Soft X-ray tomographic reconstruction of JET ILW plasmas with tungsten impurity and different spectral response of detectors

•Status of the soft X-ray diagnostics at JET with respect to tungsten influx studies is reviewed.•In tomography, we introduce a new method to correct differences in spectral response of detectors.•Data analyses of two JET discharges (with and without tungsten influx) are presented.•It is demonstrated that the corrections are robust but not very large.•We conclude that tomography is reliable in spite of the differences in spectral response. The Joint European Torus (JET) presently operates with the ITER-like wall (ILW) including tungsten divertor. Analyses of the soft X-ray radiation (SXR) data present an important tool for studies of transport of tungsten into JET plasmas. SXR spatial distribution can be measured by horizontal (H) and two vertical (V,T) pinhole cameras. Tomographic reconstruction of SXR emissivity from their data is challenging due to different spectral sensitivities of the cameras which can cause significant inconsistencies due to spectral properties of tungsten radiation. In this contribution an advanced correction based on evaluation of the sensitivity differences for individual lines of view of the SXR detectors is presented. The adjustments take into account atomic data of tungsten as well as the SXR intensity perturbation due to tungsten influx. First results are presented and discussed.