HCAL, the hadron calorimeter

The hadron calorimeter is made out of iron slabs which compose the magnet return yoke.

The calorimeter is made out of a cylindrical part called the barrel and two end caps to close the barrel. The barrel has 24 half-modules and each end cap has 6 modules. The end caps have sort of a plug penetrating in the barrel, this is meant to improve the homogeneity of the magnetic field. You can see the structure in perspective. The end caps are greenish and the barrel pink, the upper barrel modules have been made transparent to show the plug structure. It can also be seen projected along the beam axis, or in a transverse view.

Structure of the calorimeter modules

The modules from barrel and end caps have the same internal structure.

Structure of the sensitive medium

The sensitive medium is a wire chamber made of a comb in extruded PVC. The wires run between the teeth. The comb is closed by a cathod cut into pads. The pads are interconnected to build a tower looking toward the interaction point.

More precise drawings can be obtained from the postscript files: along the beam axis, transverse view, global perspective.