The ATLAS hadronic endcap calorimeter

The construction of the ATLAS hadronic endcap calorimeter is nearing completion. Beam tests of the series modules have been completed. The performance of the modules yields a resolution for electrons of sigma (E)/E=(21.4+or-0.2)% (GeV)/sup 1/2// square root E(+)(0.3+or-0.2)% and for pions of sigma (E)/E=(70.6+or-1.5)% (GeV)/sup 1/2// square root E(+)(5.8+or-0.2)%, where (+) denotes a quadratic sum. The uniformity and linearity have been verified. The details of the electronic readout chain are well understood and allow precision predictions for the performance of the calorimeter under the final ATLAS operating conditions. (5 refs).