Hadron Calorimeter with Proportional Tubes and Pad Readout

A sampling gas hadron calorimeter with tower readout geometry has been constructed for E687 at Fermilab. This photoproduction experiment will run in the new wide band photon beam capable of producing photons of energy up to 500 GeV/c. The calorimeter consists of 28 120"×82"×1.75" Fe plates interspersed with planes of extruded aluminum proportional tubes. The readout is achieved with capacitively induced signals on pads with a cylindrical geometry. The electronics is constructed from surface mount devices mounted at the detector and includes a preamplifier, pole zero filter, amplifier, and cable driver. The system has a dynamic range spanning the region from minimum ionizing particles (mip) up to a few hundred mip\´s. The calibration will be monitored using muons and electronic test signals. The gas gain will be monitored by recording the pulse height of an Fe55 source with a cylindrical proportional tube. Results on the details of construction, pad readout, and electronics are presented.