High-pT Trigger Detector Development for the ALICE Experiment at CERN

Theoretical considerations and experimental measurements indicate the importance of charged hadron identification in the higher pT region (namely pT>10GeV/c). Since the PID capability of the present ALICE experiment at LHC (CERN) is based on statistical methods at large transverse momenta, the construction of a new detector to improve the track by track PID capability is very much supported. This task can be fulfilled by a gaseous ring imaging Cherenkov (RICH) detector. However, high-pT events are very rare, thus to enrich the statistics of the rare high pT events in the recorded data sample the construction of a dedicated trigger unit for the RICH detector is strongly recommended. To select the high-pT events the basic idea is to detect the inclination of the charged particle trajectories in the ALICE magnetic field with respect to the direction of the collision point. If the inclination is smaller than a threshold, the transverse momentum of the propagating particle is larger than a certain value. A prototype chamber using Thick Gas Electron Multiplier layers was built to test the operation principle of the High-pT Trigger Detector. The prototype was tested at the CERN PS beam facility. We present results of the operation tests and data taking. Monte Carlo simulations in the ALIROOT framework are also performed in order to optimize the geometry and segmentation of the detector we present here. In this paper we summarizes our efforts to develop the High-pT Trigger Detector.