Measurement of the low-energy quenching factor in germanium using an
  $^{88}$Y/Be photoneutron source
  We employ an $^{88}$Y/Be photoneutron source to derive the quenching factor
for neutron-induced nuclear recoils in germanium, probing recoil energies from
a few hundred eV$_{nr}$ to 8.5keV$_{nr}$. A comprehensive Monte Carlo
simulation of our setup is compared to experimental data employing a Lindhard
model with a free electronic energy loss $k$ and an adiabatic correction for
sub-keV$_{nr}$ nuclear recoils. The best fit $k=0.179\pm 0.001$ obtained using
a Monte Carlo Markov Chain (MCMC) ensemble sampler is in good agreement with
previous measurements, confirming the adequacy of the Lindhard model to
describe the stopping of few-keV ions in germanium crystals at a temperature of
$\sim$77 K. This value of $k$ corresponds to a quenching factor of 13.7 % to
25.3 % for nuclear recoil energies between 0.3 keV$_{nr}$ and 8.5 keV$_{nr}$,
respectively.
