Sep 8 – 14, 2019
Toyama International Conference Center
Japan timezone

ZICOS experiment for neutrinoless double beta decay search using Zr-96

Sep 12, 2019, 4:10 PM
203 (Toyama International Conference Center)


Toyama International Conference Center
Oral presentation in parallel session Neutrinos Neutrino #23


Prof. Yoshiyuki Fukuda (Miyagi University of Education)


ZICOS is new experiment of neutrinoless double beta decay (0$\nu\beta\beta$) search using $^{96}$Zr isotope. We have developed a liquid scintillator containing a tetrakis (isopropyl acetoacetato) zirconium (Zr(iPrac)4), and the performance of our liquid scintillator is that a light yield is $48.7 \pm 7.1$% relative to BC505, and an energy resolution is $2.6 \pm 0.5$% at 3.35MeV assuming 64% photo coverage of the photomultiplier for 10wt.% concentration of Zr(iPrac)4$ solution. In order to investigate a half-life of 0$\nu\beta\beta$ over 10$^{27}$ years, which corresponds to neutrino mass less than 0.01eV, we have to use tons scale of $^{96}$Zr isotope. At present, we are planning to construct a spherical detector similar to KamLAND-Zen, however we have to reduce 95% of backgrounds from $^{208}$Tl decay which should be adhere on the surface of inner balloon as observed by KamLAND-Zen. For this purpose, we have developed new technique to use Cherenkov light in order to reduce those backgrounds using the topology of location for photomultipliers received Cherenkov light, and have obtained the results of Monte Carlo simulation that 93% of $^{208}$Tl decay events could be reduced with 78% efficiency for 0$\nu\beta\beta$ events using the topological information. In this points of view, we have to use the pulse shape for the discrimination to extract Cherenkov lights, and have to demonstrate the topological information of hitted PMT location using actual low energy electrons. Here we will report recent developments and discuss about the prototype ZICOS detector which will demonstrate such a topological information.

Primary author

Prof. Yoshiyuki Fukuda (Miyagi University of Education)


Prof. Izumi Oagwa (Applied Physics, Faculty of Engineering, University of Fukui,) Dr Katsuki HIraide (Kamioka Observatory, ICRR, University of Tokyo) Prof. Shigetaka Moriyama (Kamioka Observatory, ICRR, University of Tokyo) Dr Shunsuke Kurosawa (Institute for Material Research, Tohoku University) Prof. Takahiro Gunji (Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science)

Presentation materials