Development of a Timepix based detector for the NanoXCT project

The NanoXCT EU FP7 project [1] aims at developing a laboratory, i.e. bench top sized X-ray nano-CT system with a large field-of-view (FOV) for non-destructive testing needs in the micro- and nano-technology sector. The targeted voxel size is 50 nm at 0.175 mm FOV, the maximum FOV is 1 mm at 285 nm voxel size. Within the project a suitable X-ray source, detector and manipulation system have been developed. The system concept [2] omits the use of X-ray optics, to be able to provide a large FOV of up to 1 mm and to preserve the flexibility of state-of-the-art micro-CT systems. The targeted resolution will be reached via direct geometric magnification made possible by the development of a specialized high-flux nano-focus transmission X-ray tube. The end-user's demand for elemental analysis will be covered by energy-resolved measurement techniques, in particular a K-edge imaging method. Timepix [3] modules were chosen as the basis for the detector system, since a photon counting detector is advantageous for the long exposure times that come with very small focal spot sizes. Additional advantages are the small pixel size and adjustable energy threshold. To fulfill the requirements on field-of-view, a detector width > 3000 pixels was needed. The NanoXCT detector consists of four Hexa modules with 500 mu m silicon sensors supplied by X-ray Imaging Europe. An adapter board was developed to connect all four modules to one Fitpix3 readout. The final detector has an active area of 3072 x 512 pixels or approximately 17 x 3 cm(2). In this contribution we present the development of the Timepix based NanoXCT detector, it's application in the NanoXCT project for CT and material specific measurements and the current status of results.