Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments.

Area of Science:

• Nuclear Physics
• Particle Physics
• Chemistry

Background:

• Neutrinoless double beta decay is key to determining if neutrinos are Majorana particles (their own antiparticles).
• The extremely long half-life of this decay necessitates highly sensitive detection methods to distinguish it from background radioactive processes.
• Detecting the daughter atom, such as Barium-136 (Ba2+), offers a robust signature for neutrinoless double beta decay of Xenon-136 (Xe).

Purpose of the Study:

• To advance the development of a 'barium-tagging' experiment for detecting neutrinoless double beta decay.
• To create a sensor capable of identifying single Ba2+ ions within a high-pressure xenon gas detector.

Main Methods:

• Proposed a fluorescent bicolour indicator as the core component of a single Ba2+ ion sensor.
• The sensor design involves a monolayer of indicators that capture Ba2+ ions, forming a species with unique photophysical properties.
• Detection relies on observing the indicator's response to laser interrogation, signaling the presence of a single Ba2+-coordinated ion.

Main Results:

• Demonstrated a significant advancement towards a barium-tagging experiment by proposing a method for single Ba2+ ion detection.
• The proposed fluorescent indicator system shows potential for identifying single Ba2+ ions in high-pressure xenon.

Conclusions:

• The developed sensor technology is a critical step for future barium-tagging experiments searching for neutrinoless double beta decay.
• This approach offers a promising pathway to confirm the nature of neutrinos and their antiparticle properties.