Weapons which use ionizing radiation as their primary means of damaging targets. Thus, they can penetrate virtually all types of spacecraft armor to irradiate targets inside.

Types

An early form of radiogenic weapon is the x-ray bomb, a nuclear warhead tuned to produce a pulse of x-rays from a lasing medium as it detonates. This principle was later developed into dedicated x-ray lasers. In both cases the only defense is several meters (or more) of dense material such as lead, unfeasible for spaceships.
Other types include particle beams which produce a spray of radiation when they strike a ship's hull, and neutron guns. Use by infantry in atmospheres is ill-advised as backscatter will irradiate the firer.

Legislation

Widely considered inhumane, they are internationally banned in modern times and their use constitutes a war crime. Weapons producing radiation as a side-effect (such as nuclear bombs) are still allowed, using ionizing radiation as a weapon is not.