The TREX-BB-0 or NEXT-0-MM setup consist of a small chamber able to hold high pressure (up to 10 bar) very pure gas. The chamber has an active volume of 2:2 liters (10 cm in height, 16 cm in diameter) constructed with ultra-high vacuum specifications and is rated for operation at 15 bar. Inside the chamber, two circular copper plates (10 cm in diameter) form the drift/conversion region that can be adjusted from 1 to 6 cm. The bottom plate can host sample microbulk Micromegas readouts, typically having 35mm diameter.


The chamber is connected to a complex gas system that allows to mix, filter, recirculate recover, pump and monitor the chosen gas mixture in the chamber (for technical details of the system refer to our publications)

The setup has been used to test Micromegas readouts in different conditions of gas composition and pressure and to characterized new gas mixtures. The most relevant result up to now is the characterization of microbulk Micromegas in Xe +  trimethylamine (TMA) mixtures at pressures from 1 to 10 bar. This is a Penning mixture that allows to operate reliable at high gains, while keeping very good energy resolutions (see publications)

Currently the setup has been modified to study the ionization properties of alpha particles in this mixture, in particular the ion-electron recombination dependence on the angle of the alpha track with the electric field.