Abstract :
The Readout Electronics for the Time Projection Chamber (TPC) of the ALICE experiment at the CERN LHC consists of 557578 readout channels, each comprising a shaping-amplifier circuit, a 10-bit 10-MSPS ADC, and a digital circuit for the baseline subtraction, tail cancellation, zero suppression and data buffering. The complete readout chain is contained in Front End Cards (FEC), with 128 channels each. A number of the FECs (up to 25) are controlled by a Readout Control Unit (RCU), which interfaces the FECs to the Data Acquisition system DAQ, the Trigger, and the Detector Control System (DCS). The ALICE TPC readout electronics is running successfully since the start of the LHC in November 2009 both with p-p and Pb-Pb collisions. While recording zero suppressed data from p-p collisions at an interaction rate of up to 100 kHz, the TPC readout featured a maximum readout rate of 1 kHz. It is capable to achieve a readout rate of 3:3 kHz for empty events, which is unprecedented for large TPCs. For Pb-Pb collisions, the TPC readout electronics is capable of recording the zero suppressed data at the maximum rate of 250 Hz for central collisions, whereas empty events can be read out at a maximum rate of 1.25 kHz. This performance is presented for the first time in this paper.
Keywords :
nuclear electronics; particle calorimetry; readout electronics; time projection chambers; 10-bit 10-MSPS ADC; ALICE TPC readout electronics; ALICE experiment; CERN LHC; Pb-Pb collision; baseline subtraction; complete readout chain; data acquisition system; data buffering; detector control system; digital circuit; front end cards; interaction rate; maximum readout rate; proton-proton collision; readout channels; readout control unit; shaping-amplifier circuit; tail cancellation; time projection chamber; zero suppression; Backplanes; Detectors; Economic indicators; Europe; Field programmable gate arrays; Large Hadron Collider; Random access memory;