Upgraded high-resolution X-ray diagnostics on JET is expected to monitor the plasma radiation emitted by W46+ and Ni26+ ions at 7.8keV and 2.4keV photon energies, respectively. Both, X-ray lines will be monitored by new generation energy-resolved micropattern gas detectors with 1-D position reconstruction capability. The detection structure is based on triple GEM (T-GEM) amplification structure followed by the strip readout electrode. This article presents a design of new detectors and prototype detector tests.