A Particle Accelerator is a device that uses giant magnets to fire billions of subatomic particles into their anti-particles at the speed of light to create miniature big bangs.
The particle accelerator owned by Isodyne Energy was located in the company's headquarters in Pasadena, California. Jane Scott worked with the machine there; her exposure was so extensive that, upon her death, she glowed in the dark. The glow of her corpse caused Strategic Scientific Reserve scientist Aloysius Samberly, upon inspection, to know that she worked with a Particle Accelerator.
Tony Stark's Accelerator
Tony Stark constructed his own small scale particle accelerator in the basement levels of his home in order to create a new element whose structure was discovered by Howard Stark, who hid its schematics in a model for the Stark Expo.
Using an intensified stream of subatomic particles from the accelerator, Tony was successfully able to synthesize his own new element, which he then used to create a more stable, perfected version of the Arc Reactor.
StatiCorp, a subsidiary of the Roxxon Corporation, designated and constructed a particle accelerator, in an attempt to create an inter-dimensional portal, after the phenomenon known as the Convergence took place in London, showing portals to each of the Nine Realms in the sky.
After many reports coming from section 2 of the Particle Accelerator, complaining that the coupling assembly was coming loose at the bolts, the part was replaced and triple-checked for damage, and tests with the accelerator continued.
Soon after, an explosion caused from a loose coupling took place in the StatiCorp Facility, killing three people, (Frank Delacourt, Jack Benson and Arlene Willoughby), and producing a burst of energy that created a portal to another world.