Last November, a very important milestone has been achieved in T-REX. The largest Micromegas prototype of the T-REX laboratory so far, the NEXT-MM detector, is operating at 10 bar of a mixture of Xenon and TMA (trimethylamine). This is the nominal operation pressure for which NEXT-MM was designed. Although previous runs at lower pressure (see references below) anticipated a successful extrapolation at 10 bar, full high pressure deployment was delayed by a number of technical issues. Operation at high pressure allows to confine high energy electron tracks in the chamber volume, and study the detection performance in conditions very close to that of a full double beta decay experiment. The plots below show a real event registered by the chamber, corresponding to a 1200 keV electron, produced by a photon from a Na22 source producing a photoelectric effect in the chamber gas. The pixelised Micromegas readout of the detector allows to image the ionization signature of the interaction. The 2D projection on the readout (on the right) and its 3D reconstruction (on the left) by means of the different arrival times in each pixel show the expected electron straggling ionization path ending in a “denser” blob
The detector is continuously acquiring more data that is currently in the process of being analyzed.
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