Speaker
Description
We are developing a high‑pressure xenon gas time projection chamber (TPC) to search for neutrinoless double beta decay (0νββ). Observing 0νββ would reveal a key unresolved property of neutrinos—whether they are Majorana particles. Because 0νββ is an extremely rare and monoenergetic process, the detector must simultaneously achieve a large target mass, excellent energy resolution, and ultra‑low background. A high‑pressure xenon gas TPC is a promising candidate: large mass is obtained by operating at high pressure, high energy resolution is realized using gaseous xenon with electroluminescence amplification, and low background is achieved through event‑by‑event track reconstruction.
We are developing an original readout structure, the Electroluminescence Collection Cell (ELCC), installed on the readout plane of the high‑pressure xenon gas TPC. The ELCC is a pixelated electroluminescent light‑readout mechanism that enables both high energy resolution and detailed track reconstruction. To date, we have demonstrated the ELCC concept using a small 10‑L prototype and evaluated its performance at the 0νββ Q‑value (2.5 MeV) with a larger 180‑L prototype. We are also developing larger, multi‑channel devices to gain operational experience toward a physics‑scale 1000‑L detector. For example, as feedthrough discharge becomes a concern at longer drift lengths, we are preparing to operate a CW boost circuit inside the vessel and to modularize the readout system for improved reliability.
In this workshop, we will present the performance of our high‑pressure xenon gas TPC and the current status of its technological development.