  Cosmic ray muon has strong penetrating power and no ionizing radiation
hazards, which makes it an ideal probe for detecting special nuclear materials.
In this paper, a high spatial resolution muon tomography system based on
Micromegas detectors is proposed to optimize the imaging time and quality. The
proposed system includes eight Micromegas detectors based on the thermal
bonding technique and a scalable readout system. In addition, a multiplexing
method based on position encoding is developed to reduce the number of
electronics channels by order of magnitude. The spatial resolution of the
proposed system with encoding readout can reach a value of hundred micrometers.
Finally, a tomography test is performed, and test results show that this
proposed system can image 2-cm objects and distinguish different materials.
