Since a large area (~150 square meters) has to be covered, a gaseous detector is the only choice.
In the framework of the LAA project at CERN an intensive R&D programme has proved that the best
solution for the Time of Flight detector is the Multigap Resistive
Plate Chamber (see the following figure).
The key aspect of this technology is that the electric field is high and uniform over the whole sensitive gaseous volume of the detector. Any ionisation produced by a through-going charged particle will immediately start a gas avalanche process which will eventually generate the observed signals on the pick-up electrodes. There is no time jitter associated with the drift of the electrons to a region of high electric field.