[calenel]

All that matters is that the signal arrive at the shaped charges to insure that the compression wave is close enough to spherical to sustain the required geometry. You don't need exploding foil detonators or any of the other crap. If you wanted to make sure your bomb did not go off in the silo or on the bomber, and if you had the resources of a superpower, and if you were deterring other nuclear powers and if you had special needs such as the weapon being able to withstand multiple g's and to go off at a precise altitude, withstand shock waves and high intensity radiation or concussion, then, yeah, you might need some or all of that junk.

Krytrons and exploding foil detonators were not in use during WWII, yet atomic bombs were. I wonder how that could be?

[Southack]

"All that matters is that the signal arrive at the shaped charges to insure that the compression wave is close enough to spherical to sustain the required geometry."

No, close doesn't cut it. The implosion has to be utterly perfect.

A California university recently duplicated a Georgia university's experiment in which deuterium acetone was blasted with ultrasound. That liquid then formed bubbles. The perfect bubbles eventually imploded while creating a neutron event (i.e. fission or fusion). The imperfect bubbles just imploded. No neutron event.

The difference between an imperfect bubble and a perfect bubble is minute, but it makes all of the difference between a neutron event or a non event.