Particle beam weapon

For the Particle Beam Rifle, see here.



A particle beam weapon is a type of directed energy weapon that uses an ultra-high energy beam of atoms or electrons to damage a target by disrupting its atomic and molecular structure.

Beam generation
A neutral particle beam weapon ionizes hydrogen gas by either stripping an electron off of each hydrogen atom, or by allowing each hydrogen atom to capture an extra electron. When hydrogen gains electrons it forms negative ions (anions); when hydrogen atoms lose electrons they form positive ions (cations). A particle beam weapon that accelerates anions uses a traveling-wave type particle accelerator. In this kind of accelerator, the negative ions are released inside a cylindrical ion acceleration chamber. This chamber has an electrode with an alternating electric charge of up to 1,000,000,000 volts inside it.

The firing process contains the following stages:


 * 1) While the charge on the electrode is positive, the ions are attracted to the negative charge on the electrode, and thus bunched around it.
 * 2) The alternating voltage switches the charge to negative on the accelerating electrode.
 * 3) The negative charge electrostatically repels the negative ions and accelerates them to near the velocity of light.
 * 4) The resulting high energy beam of anions passes through a chamber filled with low pressure gas.
 * 5) There, collisions with the gas strip the extra electrons from the anions, and thus make the particle beam neutral.
 * 6) The particle beam proceeds straight to its target, and damages it by disrupting its molecular structure with kinetic energy.

Cyclotron particle accelerators, linear particle accelerators, and synchroton particle acclerators can accelerate positively charged hydrogen ions until their velocity approaches the speed of light, and each individual ion has a kinetic energy range of 100-1000 megavolts or more. The resulting high-energy protons capture electrons from electron emitter electrodes, and are thus electrically neutralized. This creates an neutral beam of high-energy hydrogen atoms that can proceed at nearly the speed of light to strike a target.

The pulsed particle beam emitted by a particle beam weapon may contain up to 1 gigajoule of kinetic energy or more. The speed of a beam approaching the speed of light (186,000 miles per second) in combination with the energy created by the weapon would negate any realistic means of defending a target against the beam.

Known particle beam weapons
So far, even though the UNSC has an understanding of this technology, only the Covenant have shown the technological aptitude to engineer practical particle beam weapons, equipping their larger warships with energy projectors capable of dealing tremendous damage to ships and planets, and using the far smaller Type-50 Sniper Rifle System as a high-accuracy anti-personnel weapon.

The Forerunner Sentinel Beam is a particle beam weapon which fires a stream of superheated, negatively-charged ions. This technology was reverse-engineered by the Covenant in form of the Type-52 Special Applications Rifle. The Forerunners also used particle-based weaponry such as the Binary Rifle.

List of appearances

 * Halo 2
 * Halo 3
 * Halo 3: ODST
 * Halo: The Cole Protocol
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Halo: Uprising