This is simply incorrect, unless you are referring to nuclear radiation. The majority of a nuke’s damage in atmosphere is caused by the pressure wave of the bomb.
See this link
http://www.projectrho.com/public_html/rocket/spacegunconvent.php#warhead
What is incorrect?! I tell you the same thing: the majority of a nuke’s damage in atmosphere is caused by the pressure wave of the bomb, which is decreasing much faster (roundly with inversely cubic proportional law), than a gamma wave, that initially caused this air pressure wave!
Yet another try.
Initial energy burst of nuke is - what? - yes, gamma photons with some tail of other energy forms.
In air these gamma quants will absorb mostly in first hundreds of meters, causing overheated initial air ball.
So nuke energy in air is delaminating on impact factors, proceeding to the target in this order:
1. The rest (small part) of gamma wave, that wasn't absorbed in air.
2. X-ray, UV, visual and IR reemissions - even less dangerous for ships, because it's small part of nuke's energy too, and it's stretched out comparinf to initial gamma wave.
3. Compressed air pressure wave (caused by rather small part of overall nuke's energy, much slower and less dense comparing to initial gamma wave, but it's enough to take down most non-armoured targets, though armoured battle machines are quite staunch to this blow).
4. Air, water and ground heat wave - the most energy-capacious, but not very dangerous, except if your target is over or under explosion point.
5. Long-term radiation - well, not a danger for TN ships and GF.
Notice the way in which nuke's energy in air is delaminating, stretching and slowing down.
Yes, p.3 (compressed air pressure wave) is the most dangerous, but it's the most dangerous comparing with other impact factors in air, not comparing with impact factors in vacuum! In fact most of nuke's energy in air will be wasted on heating air ball, that will further lift itself over explosion point.
Comparing with vacuum impact factors - it's smth completely different! No air - no absorbtion of initial gamma wave. No no slowing down, no delamination, no stretching in the volume of the air ball - nearly all the energy impact is moving with the speed of light in one microsecond-length wavefront. All the energy, that caused air pressure wave - all that energy is traveling now (in vacuum) to the target too, but in other form. And in addition to this, in the same form of microsecond-length gamma wavefront you'll take nearly all other parts of nuke: all those gamma quants, that was wasted or slowed down in air - all that gamma you'll instantly take on your ship's shell.
You think, obviously, that this shell (ship's hull) is quite capable of absorbing this damage. Yes, that's what I trying to tell: it will be absorbed! It will be absorbed in microseconds. There is no way to take it away safely: gamma is very stubborn thing, it's nearly impossible to reflect, because gamma photons have very high energy, so they are just tearing electrons off the material, no way to reflect (instantly reemission) that much energy with any material's surface. So, nearly all the energy will cause heat. The Heat! And not in the air in all the way to the target! All that heat - target's sectional area's part of nuke's energy - will be delivered instanly, without delamination and stretching, nealy withoul losses - and what do you think, the ship will safely dodge all this energy? No way. It will evaporate some part of the shell, as I wrote above, and this evaporation will be in INSTANT. What is instant evaporation of some dense matter? Yes, it's explosion! Some part of ship's hull will just explode. Explode with much more brisance, then any brisant explosive you can imagine (because no chemical brisant can release this much energy so quickly), and that will be much more part of nuke's energy, than in compressed air wave.
No miracles! If you take more energy in less time length with the same area - you'll suffer more damage.