Neutron imaging with a Micromegas detector

Due to its performances for neutron detection, the micropattern gaseous detector Micromegas is designed for neutron imaging. In this paper will be presented new results obtained with thermal neutrons near Orphee reactor at CEA Saclay. The goal of studies with a bi-dimensional detector was to tune different parameters in order to achieve the best spatial resolution which is around 160 mum (defined as the standard deviation) in double amplification mode and 180 mum in classical mode. Several 2D imaging tests have been carried out and an example, which shows different problems inherent in the substrate manufacturing, will be presented. Then, a tomographic section of a multi-wires cable, achieved with a one-dimensional Micromegas, will be presented. The high number of pillars sustaining the micromesh has lead to local inefficiencies, disturbing the tomographic reconstruction, but this result, the first tomography carried out with this kind of detector, is very encouraging.