A plasma rifle is a Covenant directed energy weapon that uses superheated ionized gas called Plasma instead of projectile ammunition. The weapon has a power output of 100-150 KV @ 2~3 dA, and can fire 360~540 rounds per minute. Unlike the Plasma Pistol, the plasma rifle is capable of semi-automatic, and full automatic fire, this is thanks in part to its dual plasma collimator design. Placed atop one another, these collimators fire in a "stagger" taking the slow automatic fire of each individual collimator and combining it, this design allows a faster rate of fire and more rounds per second, which adds to the lethality of the weapon. The Type-25 DER is the primary weapon of the Covenant’s officer corps, used by Elites and Brutes, although Jackalsand Grunts have been seen using this weapon, but not as common. Against UNSC infantry, the Type-25 rifle's lethality is considerably greater than its counterpart the Type-25 pistol, due to the faster rate of fire, injuries inflicted to the victim are severe third-degree burns, with the wound being cauterized instantly upon impact. Even near misses will produce severe burns and heat trauma. Should the plasma impact an object, the impact can create fragments that may come into contact with a victim, with a crippling or lethal effect. Generally two hits from either a plasma pistol or plasma rifle will kill a light, or non armored target. Like its counterpart, over extended periods of firing can overheat the weapon, causing it to become unusable for a short period of time. In the context of the Halo games, all of the plasma weapons' strength and lethality are compensated for both the sake of ESRB rating and gameplay. The Covenant boast a large arsenal of weapons: Most of them plasma-based. Most of the Covenant's weaponry uses a form of magnetic channeling that the human race has only applied in the MAC gun aboard starships and the Warthog-mounted M68 Gauss Cannon and the M99 Sniper Rifle.
Plasma-based weaponry is very effective against energy shielding and body armor. The amount of shots that can be fired tends to be very high, but power cannot be recharged and by firing many or powered shots in a short duration can cause the weapon to overheat, which reduces energy efficiency as well as forcing a temporary cooling period in which the weapon cannot be fired. Once the plasma reserves are used up, the weapon is useless except as a melee weapon.I got this information on halopedia.com
The Halo Array is a network of seven ring-shaped artificial worlds created by the Forerunners in order to kill all sentient life within range of the array, virtually the entire galaxy. Rather than as a weapon of war, these were used as a last resort against the Flood, a parasitic extra-galactic species that threatened to infest every lifeform in the galaxy. By activating the rings, the Forerunners denied the Flood access to these lifeforms, effectively starving the species to virtual extinction, though it clung to life in a number of Forerunner facilities, including some Halo installations.The two known Halo installations, referred to as Alpha Halo and Delta Halo respectively, orbit gas giants, though it is not known whether this is the case of all the Halos, and Alpha Halo maintained an atmospheric mining facility until it was destroyed by the Covenant. Though separated by thousands of light-years, the seven installations are networked together and capable of remote activation at the Ark, an installation outside the galaxy. Each Halo installation has a maximum effective range of 25,000 light-years. The exact means the array uses to conduct this "mass sterilization protocol" are unknown, though it is assumed to utilize energy in some type of form.
The Halo Array in its entirety has been fired once in known history, approximately 100,000 years ago, by the Didact in order to stop the Flood from overwhelming the galaxy. Despite being the network's builders, the Forerunners were killed in this last suicidal attempt to save the rest of the universe from a worse fate. The array has nearly been activated three times since; Alpha Halo was almost activated by the Master Chief before being deactivated by Cortana, while Delta Halo was activated by Commander Miranda Keyes, forced by the Jiralhanae Chieftain Tartarus, and Sergeant Johnson was forced by the Prophet of Truth to activate the Ark. None of these attempts were successful. A replacement Halo for the destroyed Alpha Halo was activated outside of the array's range, eliminating the freed Flood, but did not activate the rest of the array.
Each Halo Installation is given a designation number, from 01 to 07, and is overseen by a Monitor. The Monitors are given control of the Installations' Sentinels,Constructors and Enforcers, and are responsible for containing the Flood test subjects in their research facilities and protecting the Halo from intruders.
The Array also encompasses an installation known as The Ark or Installation 00, from which the array can be remotely and safely activated while out of firing range, and able to survive the effects.The Forerunners also built active Shield Worlds, Micro Dyson Spheres encased in a slipspace field with their own star in the center and a habitable environment, as a means to escape the effect without having to leave the galaxy.I have got this information from halopedia.com
