  Timing-pick up detectors with excellent timing resolutions are essential in
many modern nuclear physics experiments. Aiming to develop a Time-Of-Flight
system with precision down to about 10 ps, we have made a systematic study of
the timing characteristic of TOF detectors, which consist of several
combinations of plastic scintillators and photomultiplier tubes. With the
conventional electronics, the best timing resolution of about 5.1 ps ({\sigma})
has been achieved for detectors with an area size of 3x1 cm2. It is found that
for data digitalization a combination of TAC and ADC can achieve a better time
resolution than currently available TDC. Simultaneously measurements of both
time and pulse height are very valuable for correction of time-walk effect.
