Matter/antimatter reactor

What is antimatter? Antimatter particles are particles with the opposite charge and spin of another particle, but the same mass. When matter and antimatter collide it results in mutual annihilation, which produces energy. How much energy? A gram of matter and antimatter would produce 20 kilotons worth of energy.(20,000 tons of T.N.T exploding.)

Antiparticles can be generated by colliding subatomic particles. In general, the energy required to do this makes antimatter power inefficient for widespread use, well it could be useful is on a spaceship as a storage space saver. Antimatter power is not commenely used by advanced races with access to advanced fusion reactors, micro fusion initiators, dalerite /rubium fission reactors, ect, do to the extreme danger of antimatter.