Functional testing of the ATLAS SCT barrels

The ATLAS SCT (semiconductor tracker) comprises 2112 barrel modules mounted on four concentric barrels of length 1.6 m and up to 1 m diameter, and 1976 endcap modules supported by a series of nine wheels at each end of the barrel region, giving a total silicon area of 60m2.The assembly of modules onto each of the four barrel structures has recently been completed. In addition to functional tests made during the assembly process, each completed barrel was operated in its entirety. In the case of the largest barrel, with an active silicon area of approximately 10m2, this corresponds to more than one million instrumented channels.This paper documents the electrical performance of the four individual SCT barrels. An overview of the readout chain is also given.