  Recently, a search for milli-charged particles produced at the LHC has been
proposed. The experiment, named milliQan, is expected to obtain sensitivity to
charges of $10^{- 1} - 10^{-3}e$ for masses in the 0.1 - 100 GeV range. The
detector is composed of 3 stacks of 80 cm long plastic scintillator arrays read
out by PMTs. It will be installed in an existing tunnel 33 m from the CMS
interaction point at the LHC, with 17 m of rock shielding to suppress beam
backgrounds. In the fall of 2017 a 1% scale "demonstrator" of the proposed
detector was installed at the planned site in order to study the feasibility of
the experiment, focusing on understanding various background sources such as
radioactivity of materials, PMT dark current, cosmic rays, and beam induced
backgrounds. The data from the demonstrator provides a unique opportunity to
understand the backgrounds and to optimize the design of the full detector.
