  The ATLAS inner detector is used to reconstruct secondary vertices due to
hadronic interactions of primary collision products, so probing the location
and amount of material in the inner region of ATLAS. Data collected in 7 TeV pp
collisions at the LHC, with a minimum bias trigger, are used for comparisons
with simulated events. The reconstructed secondary vertices have spatial
resolutions ranging from ~200 microns to 1 mm. The overall material description
in the simulation is validated to within an experimental uncertainty of about
7%. This will lead to a better understanding of the reconstruction of various
objects such as tracks, leptons, jets, and missing transverse momentum.
