Köln 2004 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 45: Instrumentation and Applications VI

HK 45.5: Talk

Thursday, March 11, 2004, 17:45–18:00, C

TRAP - a fast tracking processor for the ALICE TRD — •Venelin Angelov — Kirchhoff Institute of Physics, University of Heidelberg, Germany

The ALICE Transition Radiation Detector (TRD) consists of 6 layers of drift chambers and radiators, arranged in a barrel geometry in the central part of the ALICE heavy-ion experiment at LHC. It is designed to track charged particles and to perform electron identification. In addition, it has the capability to provide a fast electron trigger within 6 µ s after the collision. The charges induced on the 1.2 million pads are converted to voltage pulses with a charge sensitive PreAmplifier and Shaping Amplifier (PASA). A second chip - the TRAcklet Processor (TRAP) digitizes the outputs from the PASA with 10 bit at 10 MHz. The position of each charge cluster can be calculated using the charge sharing between neighbouring pads. About 20 samples are taken for each track. The momenta are obtained from the track parameters by performing straight line fits. The TRAP chip contains the ADCs, digital filters, preprocessor, and four RISC CPUs running at 120 MHz along with their instruction and data memories, serial configuration interface and fast readout tree merger. Both chips, PASA and TRAP, are implemented on low cost custom multichip module for 18 analog channels, which looks like a standard ball grid array device. Results will be present from working prototype chips.