  Particle Flow Algorithms (PFAs) have been proposed as a method of improving
the jet energy resolution of future colliding beam detectors. PFAs require
calorimeters with high granularity to enable three-dimensional imaging of
events. The Calorimeter for the Linear Collider Collaboration (CALICE) is
developing and testing prototypes of such highly segmented calorimeters. In
this context, a large prototype of a Digital Hadron Calorimeter (DHCAL) was
developed and constructed by a group led by Argonne National Laboratory. The
DHCAL consists of 52 layers, instrumented with Resistive Plate Chambers (RPCs)
and interleaved with steel absorber plates. The RPCs are read out by 1 x 1 cm2
pads with a 1-bit resolution (digital readout). The DHCAL prototype has
approximately 480,000 readout channels. This talk reports on the design,
construction and commissioning of the DHCAL. The DHCAL was installed at the
Fermilab Test Beam Facility in fall 2010 and data was collected through the
summer 2011.
