The Hadron Cannon (ハドロン砲 Hadoron hō) was a formerly experimental weapon system, originally built into the Gawain as a testbed model, and later improved upon by Rakshata Chawla. Upon the Black Knights' acquisition of the Gawain, the system still had yet to have the beams converge wasting much of the weapon's destructive power. This flaw was patched by Rakshata Chawla when she integrated her Gefjun Disturber system into the armament using the Gefjun field to direct the Hadron blast. This system was salvaged from the damaged Gawain and installed onto the Ikaruga (which she also improved to fire at a larger range with a more powerful widespread beam). Later models of Britannian units started implementing similar technology found in models such as the Mordred and the Gareth.
Other variations of the Hadron Cannon are the Hadron Blaster and the Stark Hadron Cannon. The Shinkirō and Percival was equipped with the hadron blaster, which fires a spherical burst shot as opposed to a straight beam. It is powerful enough to pierce through a standard Blaze Luminous. The Mordred was equipped with the Stark Hadron Cannon, which fires a much more powerful beam than the original one. According to Nina Einstein, the Stark Hadron Cannon is capable of leveling a small mountain.
Hadrons are particles made up of quarks, such as protons, neutrons, and mesons. It is probably safe to assume that the Hadron Cannon is thus some sort of particle cannon that fires Hadrons.