Speaker
Description
In experiments that look for dark matter particles or coherent neutrino nucleus scattering, we often measure the charge signal produced from the ionization of the nuclear recoil events. Nuclear recoils generate less ionization than electron recoils of the same energies, and the relative ratio, defined as the ionization yield, is crucial to calibrating the detectors. We performed a measurement of the ionization yield in silicon using a SuperCDMS HVeV detector. By using a mono-energetic, low-energy neutron beam, and observing nuclear recoils in the HVeV detector with specific scattering angles we determined the ionization yield at six different recoil energies between 100 eV and 3.9 keV. The 100 eV measurement is the lowest-energy ionization yield measurement in silicon to date. The results deviate from the Lindhard model prediction and are inconsistent with previous measurements at low energies, showing a higher than previously measured ionization yield towards lower energies.
