Orateur
Description
The AXEL (A Xe ELectroluminescence) project aims to search for neutrinoless
double beta (0νββ) decay of 136Xe using high xenon gas time projection chamber.
Electroluminescence (EL) mode is used to readout the ionization signal in order to
achieve high energy resolution. We have developed a new modularized cellular
readout method called “Electroluminescence Light Collection Cell (ELCC)”. Cells
are made as holes penetrating an PTFE board sandwiched by a thin electrode plate
with holes and a mesh. The cell interval is 10 mm. Ionization electrons are drifted
and pulled into the cells by the electric field and generate EL lights, then EL photons
are detected by VUV-sensitive SiPMs attached to that cell (Fig. 1). It has uniform
sensitivity for entire region of the detector because all ionization electrons are once
pulled into cells. Its rigid structure is an advantage to enlarge the detector.
We built a large size prototype detector with 180 L volume and 672 ch readout. The
detector performance was evaluated with 8 bar xenon gas. As a source having
similar energy as the signal (2458 keV), gamma-rays with energy of 1836 keV from
88Y is used to evaluate the energy resolution. Achieved energy resolution is 0.92 %
(FWHM) at 1836 keV. This corresponds to 0.78 % (FWHM) when extrapolated to
2458 keV. Event topology is also reconstructed as shown in Fig. 2. In the
presentation, the performance of this detector will be reported.
The construction of a new detector with 1000 L volume is on going, aiming to take
physics data. I will also present the status and prospect of this new detector.
