Speaker
Description
The NEXT collaboration searches for neutrinoless double beta decay (0νββ) using high-pressure xenon gas Time Projection Chambers (TPCs). A key advantage of this technology is the topological reconstruction of 0νββ events—a track with two highly ionizing "blobs" at its ends—which provides exceptional background rejection. However, high transverse electron diffusion in pure xenon blurs this topology and limits spatial resolution.
To overcome this, we are investigating Helium-Xenon gas mixtures. Previous studies have demonstrated that adding 10–15% helium acts as an effective electron coolant, drastically reducing transverse diffusion while preserving xenon's excellent intrinsic energy resolution.
This poster presents the ongoing experimental validation of these mixtures using the NEXT-DEMO prototype. We review the physics of electron diffusion and the simulations that motivated the use of He-Xe admixtures. Furthermore, we present the current operational status of the detector and outline our experimental program: systematically testing various He-Xe ratios to empirically characterize diffusion, evaluate detector performance, and confirm the expected improvements for future ton-scale 0νββ searches.