Forward Multiplicity Detector
The ALICE Forward Multiplicity Detector (FMD) provides a high resolution charged particle multiplicity determination at very forward rapidity, which allows ALICE to give a more complete picture of the bulk properties of the interactions in A+A collisions. The FMD is a silicon strip detector with 51,200 strips arranged in 5 rings, covering the range −3.4 < η < 5.1. It is placed around the beam pipe at small angles to extend the charged particle acceptance of ALICE into the forward regions, not covered by the central barrel detectors.
FMD extends the coverage for multiplicity of charge particles into the forward regions — giving ALICE the widest coverage of the four LHC experiments for these measurements. The FMD also provides an independent measurement of the orientation of the collisions in the vertical plane, which can be used with measurements for the barrel detector to investigate flow, jets, etc.
