# Geoneutrinos in Large Direct Detection Experiments

## TL;DR

This paper explores the potential of large direct detection experiments, especially using germanium, to detect geoneutrinos, providing new insights into Earth's interior and formation history.

## Contribution

It demonstrates the feasibility of detecting geoneutrinos in large direct detection experiments, highlighting germanium as the most promising target material.

## Key findings

- Germanium offers the lowest recoil energy threshold for detection.
- Detection of $^{40}$K geoneutrinos is possible with realistic thresholds.
- Minimum required exposure is around 10 tonne-years.

## Abstract

Geoneutrinos can provide a unique insight into Earth's interior, its central engine and its formation history. We study the detection of geoneutrinos in large direct detection experiments, which has been considered non-feasible. We compute the geoneutrino-induced electron and nuclear recoil spectra in different materials, under several optimistic assumptions. We identify germanium as the most promising target element due to the low nuclear recoil energy threshold that could be achieved. The minimum exposure required for detection would be $\mathcal{O}(10)$ tonne-years. The realistic low thresholds achievable in germanium and silicon permit the detection of $^{40}$K geoneutrinos. These are particularly important to determine Earth's formation history but they are below the kinematic threshold of inverse beta decay, the detection process used in scintillator-based experiments.