  A new experiment to quantitatively measure neutrons induced by cosmic-ray
muons in selected high-Z materials is introduced. The design of the
Muon-Induced Neutron Indirect Detection EXperiment, MINIDEX, and the results
from its first data taking period are presented as well as future plans.
Neutron production in high-Z materials is of particular interest as such
materials are used for shielding in low-background experiments. The design of
next-generation large-scale experiments searching for neutrinoless double beta
decay or direct interactions of dark matter requires reliable Monte Carlo
simulations of background induced by muon interactions. The first five months
of operation already provided a valuable data set on neutron production and
neutron transport in lead. A first round of comparisons between MINIDEX data
and Monte Carlo predictions obtained with two GEANT4- based packages is
presented. The rate of muon-induced events is overall a factor three to four
higher in data than predicted by the Monte Carlo packages. In addition, the
time evolution of the muon-induced signal is not well described by the
simulations.
