Speaker
Description
The nuclear recoil ionization efficiency or "quenching factor" (QF) plays a crucial role in low-threshold ionization type detectors aimed at detecting CE$\nu$NS and studying new physics through this channel. We present an improved model based on the integro-differential equation that describes the cascade process initiated by a nuclear recoil, which takes into account a more detailed modeling of nuclear and electronic stopping power at low energies, as well as the effect of electronic straggling. We incorporate the Coulomb repulsion effects for the electronic stopping using a semi-classical model proposed by Tilinin and other similar approaches. Our model also incorporates an energy-dependent binding energy up to the energy required to produce a Frenkel pair in a pure crystal. These effects describe the QF data available in silicon and give a rough description of recent data in germanium, up to recoil energies of about 40 eV.