The latest generation of Micromegas detectors show a good energy resolution,
spatial resolution and low threshold, which make them idoneous in low energy
applications. Two micromegas detectors have been built for dark matter
experiments: CAST, which uses a dipole magnet to convert axion into detectable
x-ray photons, and MIMAC, which aims to reconstruct the tracks of low energy
nuclear recoils in a mixture of CF4 and CHF3. These readouts have been
respectively built with the microbulk and bulk techniques, which show different
gain, electron transmission and energy resolutions. The detectors and the
operation conditions will be described in detail as well as their
discrimination capabilities for low energy photons will be discussed.Comment: To be published in the proceedings of the TIPP2011 conference
(Physics Procedia