You've got first proto's back from fab ready for testing! Now what?!
Unfortunately, valuable and scarce prototypes are difficult to commit early on to potentially damaging ESD or other transient testing risks.
But the earlier this testing is done, the more likely problems can be identified early and managed to keep the product development schedule on-track.
ESD Susceptibility scanning does not directly inject ESD energy into the system, rather it mimics the fields created nearby from the gun to allow fine-pitch susceptibility analysis without the danger of destructive zaps finding a delicate node which wouldn't be exposed or vulnerable in the final system.
Comparative Current Reconstruction can be used at non-destructive levels to characterize TVS clamping performance and the specific need for such devices on each node, whereas ESD guns cannot provide repeatable, line specific information.