Tracking within |eta| < 2.5, pT > 100 MeV where the reconstruction efficiency is low, but well understood.
Particle identification by dE/dx for ~ p < 800 MeV
EM and Hadronic Calorimetry within |eta| < 4.9, single-particle deposits reconstructible up to 4.8
Sensitivity to charged particles with p > 500 MeV, neutrals with p > 200 MeV
Triggers & Forward Detectors
Minimum Bias Trigger Scintillators: 16 counters per side (32 in all), 2.1 < |eta| < 3.8. Light yield degraded due to radiation, may be replaced at lower counter-granularity for 2016.
LUCID...
ZDC. ATLAS ZDC may not be available for ~13 TeV pp running. A ZDC capable of operating at high luminosity looks very unlikely.