Test procedures for ALICE silicon pixel detector ladders

Abstract ALICE is one of the experiments which are about to start data taking at the CERN Large Hadron Collider (LHC). It consists in an assembly of detectors aimed at allowing a complete and precise reconstruction of a typical heavy-ion collision event. Its innermost sensitive elements are two layers of silicon pixel detectors (SPD), each one consisting of a 200 μ m silicon sensor bump bonded to five electronic readout chips subdivided into 8192 ( 32 * 256 ) elementary cells. The SPD is fundamental to obtain a precise estimation of the particle momenta. It will also allow to estimate the position of primary and secondary vertices (which are important for study of heavy quarks) and to evaluate the event multiplicity before tracking. Before integration in ALICE, each sensitive and electronic readout part of the SPD must pass through a sequence of tests which ensure constant production quality, in all its operational aspects (electronic control and response, data acquisition performance and thresholds). This presentation describes the test procedure for single electronic readout chips before and after they have been bump bonded to the silicon sensors.