Position Encoding Readout Electronics of Large Area Micromegas Detectors aiming for Cosmic Ray Muon Imaging

In the State Key Laboratory of Particle Detection and Electronics of USTC, we have proposed a large area cosmic ray muon imaging project with multiple 40×40 cm
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Micromegas detector modules. 2000 strip channels are required for each detector module, which introduces great challenges to the cost and complexity of readout electronics. To overcome the challenges, a position encoding readout algorithm was proposed to reduce the number of readout channels, which is demonstrated by the Eulerian path of graph theory. In this paper, a prototype system with six Micromegas modules, each with the size of 15×15 cm
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, has been built to preliminarily verify the key techniques of detector fabrication and the feasibility of image reconstruction. This prototype system has a total of 4608 anode strips (384 strips in each X or Y dimension for one Micromegas module). With the position encoding method, only 768 electronic channels are required. An optical fiber-based electronics system, which is composed of four front-end cards (FECs) and a data collection module (DCM) is adopted for the purpose of low noise, high density readout. During joint tests, the charge and position of ground-based cosmic ray hits were recorded and the tracks were reconstructed successfully, which verified the feasibility of applying position encoding readout to muon imaging.