A general purpose DAQ system for the ILC Time Projection Chamber

A large Time Projection Chamber (TPC) is proposed as part of the tracking system for a detector at the future electron positron linear collider. The Linear Collider TPC (LCTPC) Collaboration has recently built a large TPC prototype (60 cm long, with an outer radius of 77 cm), offering some modularity to investigate various gas amplification systems (GEM or MICROMEGAS), pad sizes and geometries as well as different read-out systems. We present the new read-out system developed for this large prototype. It is based on the read-out electronics of the ALICE experiment at the LHC but several modifications have been necessary to adapt it to the expected output signals from the gas amplification systems, including a new programmable charge amplifier. After very promising results obtained in laboratory with a small TPC, the data acquisition system is now being tested since November 2008, with the large TPC prototype in an electron beam with an energy of up to 6 GeV, at DESY (Hamburg). In this paper we describe the TPC data acquisition system, enlightening the novelties and the modifications with respect to the ALICE system. We also report on the performance of the DAQ system during the test beam as well as other readout technologies under R&D.