Why Jones? The "Jones" is the easy way to write the units for D*. It stands for the name of R. Clark Jones, the fellow who invented D*. It is equivalent to (cm Hz 1/2/Watt). D* is a normalized detectivity, so one can compare the performance of detectors of different sizes and noise bandwidths. Not everyone likes to use it. But , some people still use (cps) for Hertz.
Reference: R.C. Jones, Proc. IRE 47, 1495 (1959).