Description and commissioning of NEXT-MM prototype: first results from operation in a Xenon-Trimethylamine gas mixture

Understand

A technical description of NEXT-MM and its commissioning and first performance is reported.

• Having an active volume of ~35 cm drift $\times$ 28 cm diameter, it constitutes the largest Micromegas-read TPC operated in Xenon ever constructed, made by a sectorial arrangement of the 4 largest single wafers manufactured with the Microbulk technique to date.
• It is equipped with a suitably pixelized readout and with a sufficiently large sensitive volume (~23 l) so as to contain long (~20 cm) electron tracks.
• First results obtained at 1 bar for Xenon and trimethylamine (Xe-(2 %)TMA) mixture are presented.