Because of the nature of the TAC circuitry, it is difficult to measure time intervals <10 ns with good linearity. However, many measurements involve start and stop signals that arrive within ±10 ns of each other. The solution for these situations is to insert an appropriate delay in the stop signal path. Selecting a delay in the range of 10 to 30 ns on an ORTEC Model 425A Nanosecond Delay is usually sufficient to move the timing peak into the linear region of the time spectrum. The stop delay can also be adjusted to center the features of interest in the time spectrum.