Ba${}^{2+}$ ion trapping by organic submonolayer: towards an ultra-low background neutrinoless double beta decay detector

Abstract

If neutrinos are their own antiparticles, the otherwise-forbidden nuclear reaction known as neutrinoless double beta decay ($\beta \beta 0\nu$) can occur, with a characteristic lifetime which is expected to be very long, making the suppression of backgrounds a daunting task. It has been shown that detecting (``tagging'') the Ba${}^{+2}$ dication produced in the double beta decay ${}^{136}\mathrm{Xe}\to {}^{136}$Ba${}^{+2}+2e+(2\nu )$ in a high pressure gas experiment, could lead to a virtually background free experiment. To identify these \Bapp, chemical sensors are being explored as a key tool by the NEXT collaboration . Although used in many fields, the application of such chemosensors to the field of particle physics is totally novel and requires experimental demonstration of their suitability in the ultra-dry environment of a xenon gas chamber. Here we use a combination of complementary surface science techniques to unambiguously show that Ba${}^{+2}$ ions can be trapped (chelated) in vacuum by an organic molecule, the so-called fluorescent bicolour indicator (FBI) (one of the chemosensors developed by NEXT), immobilized on a surface. We unravel the ion capture mechanism once the molecules are immobilised on Au(111) surface and explain the origin of the emission fluorescence shift associated to the trapping of different ions. Moreover, we prove that chelation also takes place on a technologically relevant substrate, as such, demonstrating the feasibility of using FBI indicators as building blocks of a Ba${}^{+2}$ detector.

References in corpus (9)

• Search for Majorana Neutrinos near the Inverted Mass Hierarchy Region with KamLAND-Zen
• The mechanism of high-resolution STM/AFM imaging with functionalized tips
• Improved limit on neutrinoless double beta decay of ${}^{76}$Ge from GERDA Phase II
• The origin of high-resolution IETS-STM images of organic molecules with functionalized tips
• Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200
• Sensitivity of NEXT-100 to neutrinoless double beta decay
• Demonstration of Single Barium Ion Sensitivity for Neutrinoless Double Beta Decay using Single Molecule Fluorescence Imaging
• Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches
• Mobility and Clustering of Barium Ions and Dications in High Pressure Xenon Gas

Cited by in corpus (2)

• A Compact Dication Source for Ba${}^{2+}$ Tagging and Heavy Metal Ion Sensor Development
• A journey to ITACA: Ion Tracking with Ammonium Cations Apparatus