Liquid Xenon detector R&D for 0v2ß search (KamXP)

Kota Ueshima

doi:10.1088/1742-6596/1468/1/012138

Abstract

The R&D for a new type of liquid xenon (LXe) detector is ongoing to search for the neutrinoless double-beta decay (0v2β). As a result of the KamLAND-Zen experiment, it is very important to realize the all active region detector for the energy deposition of the radiation. Newly developed additional BG reduction techniques will improve the sensitivity of 0v2β search in the future. Our detector concept is LXe stored in a new type of plastic scintillator vessel. The wavelength of LXe scintillation light is shifted to visible light from 175nm (VUV) on the inner surface of the vessel. Therefore, the LXe scintillation light can be detected by photon sensors which are far away from the 0v2β target nuclei. The pulse shape difference between LXe and plastic scintillator is used for the additional BG reduction. In the future, 8B solar neutrino events will be one of the dominant BGs in 0v2β search. To reduce the 8B solar neutrino BG, the directional information of the Cherenkov light might be useful. The status of LXe detector R&D to improve the sensitivity of 0v2β search is reported.

Highlights

By the discovery of the atmospheric neutrino oscillation[1], it was found that the neutrino had finite mass
We started R&D to improve the sensitivity for 0ν2β search, so called Kamioka double beta decay search using liquid xenon (LXe) stored in plastic scintillator vessel (KamXP)
In case that the α-particle emitted by the 214Po decay stops in the mini-balloon film which is a dead region for the energy deposition by radiation, the 214Bi events become BG for the 0ν2β search

Summary

Introduction

By the discovery of the atmospheric neutrino oscillation[1], it was found that the neutrino had finite mass. The diameter of the plastic scintillator vessel is only 90 cm even if 1 ton LXe is stored. In the present R&D, the PSD between LXe and plastic scintillator is used for the additional BG reduction to improve the sensitivity of 0ν2β search.

Results

Conclusion