For the detection of secondary vertices of long lived bottom and charm quarks at the proposed International Linear Collider (ILC) a DEPFET pixel detector is one of the technologically favored options. DEPFET pixel sensors, in which the amplifying transistor structure is contained in the pixel cell itself on a fully depleted bulk, are unique devices in terms of their large signal and low noise capability and their obtainable spatial resolution with very thin detectors. DEPFET pixel prototype modules with close to ILC specifications have been tested in the laboratory and, for the first time, in a 6 GeV electron test beam. The different noise sources have been calculated and compared with the measured value of ENC ≈ 225 e − for the entire system.

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