Simultaneoulsy, or a little earlier, Horst Schmidt-Böking (Germany) had also started the developement of new PSD, a little different than the one of Michel Lavollée aimed to do. The official German web site can be found at
Roentdek .
In both cases the specification of this new PSDs where extremelly demanding on the time and spatial resolutions. As a matter of fact, it is easy to get an extremelly good spatial resolution with a rather poor timing issue, or a good time resolution with a poor localisation of particles. Originately, the key point of the C.I.E.L's detectors were to achieve (with moderate resolution) a very good timing issue, and especially a extremelly good multi-hit resolution to not loose particles which hit the detector
together. The other type of detectors were actually based on the opposite trend, i.e. good spatial resolution but a (rather) poor multi-hit capability.
It is clear nowadays with the recent development of fast computers, fast electronic devices that these two kind of detector will partially fusion (hybrid-detector) within 10 years and other detectors will emerge.