# A measurement of the ionization efficiency of nuclear recoils in silicon

## TL;DR

This study measures how efficiently silicon converts nuclear recoil energy into ionization across 1.8 to 20 keV, revealing deviations from existing models at low energies.

## Contribution

It provides new experimental data on silicon ionization efficiency for low-energy nuclear recoils, highlighting discrepancies with Lindhard theory below 4 keV.

## Key findings

- Results align with Lindhard theory above 4 keV
- Data shows a faster drop in efficiency below 4 keV
- Deviations suggest need for model refinement at low energies

## Abstract

We have measured the ionization efficiency of silicon nuclear recoils with kinetic energy between 1.8 and 20 keV. We bombarded a silicon-drift diode with a neutron beam to perform an elastic-scattering experiment. A broad-energy neutron spectrum was used and the nuclear recoil energy was reconstructed using a measurement of the time of flight and scattering angle of the scattered neutron. The overall trend of the results of this work is well described by the theory of Lindhard et al. above 4 keV of recoil energy. Below this energy, the presented data shows a deviation from the model. The data indicates a faster drop than the theory prediction at low energies.