NEXT prototypes based on micromegas

The NEXT experiment searches for neutrinoless double beta decay in 136Xe in a high pressure TPC. The detector is based on electroluminescence light measured with PMT's and SiPM's. In parallel with this baseline, a R and D program based on micromegas (MMs) detectors with pixelized anode is developed as an option to detect both energy and topology of the signals. MMs are considered as a readout for TPCs in the field of rare event searches (dark matter, axions or double beta decay). They are a good option for such experiments because of their high radiopurity, robustness and good performance regarding energy resolution and pattern recognition. In the R and D line, prototypes chambers based on micromegas were constructed to study their properties at different pressures and gas mixtures and also to test microbulk micromegas in conditions where electron tracks could be fully contained. The results on the commissioning and performance of these prototypes are here presented