X-ray imaging detector based on a 2D sensitive THCOBRA with resistive line readout

A new x-ray imaging detector based on a THCOBRA micropatterned structure using simple position readout is proposed. It consists on a hybrid device that combines the properties of a THGEM and a 2D-MHSP in a single structure, having two charge multiplication stages allowing to reach the high gains needed to use resistive line readout methods. The new THCOBRA structure has a 10×10 cm² sensitive area and uses two orthogonal resistive lines located at the end of the electrodes in both sides of the structure for position sensitivity. The charge is collected in the end of each resistive line being the resulting signals digitized and processed. Therefore, from the amplitude of each pair of signals it is possible to determine center-of-gravity of the electron avalanche distribution. The detector uses a preamplification stage performed by a THGEM, followed by the THCOBRA, being operated in Ne/5%CH4 at atmospheric pressure. The energy resolution of the system was measured envisaging Energy Weighting Technique (EWT) applications. The system characterization in terms of spatial resolution is presented together with imaging examples to evaluate its performance in X-ray imaging applications.