Introduction

The sun, the blazing heart of our solar system, is not only essential for life on Earth but also a powerhouse of nuclear fusion. This remarkable process produces an incessant flow of neutrinos—tiny particles that provide invaluable insights into the sun’s inner workings. While advanced neutrino detectors are adept at capturing the sun’s current behavior, critical questions remain about its stability across the vast expanse of time, particularly over millions of years that encompass human evolution and significant shifts in climate.

The LOREX Experiment

Addressing these enduring questions is the mission of the groundbreaking LORandite EXperiment (LOREX). This ambitious endeavor requires an exact understanding of how solar neutrinos interact with thallium. Recently, an international team of scientists utilized the cutting-edge facilities at GSI/FAIR's Experimental Storage Ring (ESR) in Darmstadt, Germany, to obtain vital measurements that will enhance our grasp of solar stability throughout the ages. Their findings were published in the reputable journal, *Physical Review Letters*.

LOREX stands out as the sole enduring geochemical solar neutrino experiment still under active investigation, stemming from proposals made in the 1980s. Its goal? to gauge solar neutrino flux that reflects an astonishing four million years, coinciding with the geological timeline of lorandite ore—a significant mineral containing thallium.

Neutrino Interaction with Thallium

In a fascinating process, neutrinos generated by our sun interact with thallium (Tl) atoms found in lorandite, effectively transforming them into lead (Pb) atoms. The isotope 205Pb is of particular interest due to its remarkably long half-life of 17 million years, rendering it nearly stable over the four million-year timescale linked to lorandite.

Measuring Neutrino Cross-Section