Speaker
Description
In this work, a simulation and analysyis framework for the N$\nu$DEx experiment is presented.
N$\nu$DEx aims to search for the neutrinoless double beta decay in $^{82}$Se using a high pressure $^{82}$SeF$_6$ gas time projection chamber (TPC). Direct charge collection for the drifting ion charge carriers using low-noise CMOS charge sensors is the main feature of the experiment.
Using density functional theory and two-temperature theory, the reduced mobilities of SeF$_5^-$ and SeF$_6^-$ ions in SeF$_6$ were calculated, obtaining values of 0.444 $\pm$ 0.133 and 0.430 $\pm$ 0.129 $\mathrm{cm^2V^{-1}s^{-1}}$, respectively.
The TPC geometry, featuring a cathode–focusing plane–anode structure and a 10,000-pixel readout array, was modeled in COMSOL to compute electric fields. Signal and background events were generated with BxDecay0 and Geant4, while Garfield++ was used to simulate charge transport and signal induction. Three-dimensional tracks were reconstructed from drift-time differences using a breadth-first search algorithm.
To enhance signal–background separation, six topological variables were extracted from reconstructed tracks and used to define selection criteria. A boosted decision tree was applied for a preliminary analysis. The simulation framework thus provides a comprehensive tool for detector design and sensitivity studies in the N$\nu$DEx experiment.
