Conceptual Design Of Tomographic Soft X-Ray Detectors For Compass-U Tokamak

The COMPASS-U tokamak is designed at IPP CAS Prague. It will be a compact device that should achieve high toroidal magnetic field and high wall temperatures. In order to observe fast phenomena, photodiode arrays combined with beryllium filters and a pinhole are planned to be used as Soft X-Ray (SXR) detectors. Operational temperatures of photodiodes are typically below 100 degrees C and planned first wall temperatures as high as 500 degrees C for the later phases of operation. Therefore, an actively cooled support structure housing the detector has to be designed.Moreover, in order to obtain good inversion results the layout of tomographic diagnostics systems have to be optimised to provide the best possible coverage of the plasma. The proposed SXR system consists of two sets of detectors with different filter thickness enabling the use of the two filter method for electron temperature estimation. Both sets will share the same line of sight layout for better comparability. Optimisation of this layout is adapted for limited options of detector placement and extensive testing of tomography capabilities is performed. Results of these tests are shown for one of considered layouts.