Measurement of the
Centrality Dependence of
Charged Particle Pseudorapidity Density
with the PHOBOS Detector

The PHOBOS Detector

The BIG Picture

Selecting Collisions

Determining Centrality

Uncertainty on Npart

Detector Geometry

Vertex Finding

Tracklet Analysis

Tracklet Systematic Error

Measured dNch/dh

Centrality Dependence of dNch/dh

Comparison to SPS

Summary