Speaker
Chilo Garabatos Cuadrado
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
Description
The ALICE Time Projection Chamber, the largest of its kind, has been operated during the LHC RUN 1 and is being operated during RUN 2, with Multi-Wire Proportional readout Chambers. These chambers feature a Gating Grid which is pulsed at a maximum frequency of about 3 kHz and allows one to amplify the charge produced in triggered events and prevents ions to invade the drift region, such that space-charge distortions are minimized.
Analysis of data from LHC Run1 and first look at data from Run2 had demonstrated excellent performance both for particle identification via dE/dx and tracking. A summary of the performance will be presented.
For RUN 3 and RUN 4, where collision rates of 50 kHz are expected, our aim is to preserve this excellent performance while removing the inherent rate limitation imposed by the gating grid, such that 50 kHz read-out rate can be achieved.
To this end, a new concept for continuous readout at a minimum of space-charge build-up in the drift volume will be adopted. A novel configuration of GEM detectors has been developed that allows one to maintain excellent particle identification and effective ion trapping, by stacking four GEM foils with different hole pitches and operated under an ad hoc field configuration. Results of intensive R&D to achieve this goal will be summarized, including the demonstration of robustness against discharges.
We will also discuss the detector production phase, which is just starting, and includes extensive and repeated quality assurance to ensure the reliability of the chambers once they are installed in the TPC.
| On behalf of collaboration: | ALICE |
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Author
Chilo Garabatos Cuadrado
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
