Double hit reconstruction in large area multiplexed detectors

A novel approach is presented to unfold particle hit positions in tracking detectors with multiplexed readout representing an underdetermined system of linear equations. The method does not use any prior information about the hit positions, and the only assumption in the procedure is that single strip charge values on consecutive detector strips follow a smooth distribution. Ambiguities introduced by charge sharing from multiplexing are reduced by using a regularization technique. We have tested this method on a multiplexed 50 x 50 cm(2) Micromegas detector with 1037 strips and only 61 readout channels, using cosmic rays, and we have found that single and double clusters of hits can be reconstructed with high efficiency. In addition, simulations show that the algorithm is capable of reconstructing isolated hits in events with larger multiplicity.