About 25 years ago, in the framework of the ALICE TOF R&D effort, the time resolution of the RPC detector technology was extended to sub-100 ps by decreasing the gap width by about one order of magnitude and adopting the multigap construction method. This resolution range is interesting for particle tagging or identification by time-of-flight and opened the way to practical very large time-of-flight detectors for HEP and nuclear physics.

The 1999/09/27 an EP Detector Seminar was given on this matter, covering the main results and the first explorations in the physics of this detector.

In the present seminar we will revisit the preceding related detectors and the discovery process, summarize the applications that have meanwhile emerged and the status of the theoretical understanding of these detectors.