Ionization Efficiency Study for Low Energy Nuclear Recoils in Germanium

TL;DR

This study measures low energy nuclear recoils in germanium using internal conversion, comparing data to models and finding good agreement within 4%, providing insights for low-energy nuclear recoil detection.

Contribution

It introduces an indirect measurement method for low energy nuclear recoils in germanium using internal conversion and compares results with established models.

Findings

Most probable recoil energy is 17.5 keV.

Data agrees with Lindhard and Barker-Mei models within 4%.

Average recoil path-length is 0.014 μm.

Abstract

We used the internal conversion ($E_0$ transition) of germanium-72 to indirectly measure the low energy nuclear recoils of germanium. Together with a reliable Monte Carlo package, in which we implement the internal conversion process, the data was compared to the Lindhard ($k$=0.159) and Barker-Mei models. A shape analysis indicates that both models agree well with data in the region of interest within 4%. The most probable value (MPV) of the nuclear recoils obtained from the shape analysis is 17.5 keV with an average path-length of 0.014 $\mu$m.