Detonator

For the Ratt album see Detonator (album)

top: small nonel detonator with 25ms delay for chaining nonel tubes, middle: class B SPD detonator, bottom: class C SPD detonator

A detonator is a device used to trigger bombs, shaped charges and other forms of explosive material and explosive devices. Detonators can be found in either electrical or non-electrical form. There are three categories of electrical detonators namely; instantaneous electrical detonators (IED), short period delay detonators (SPD) and long period delay detonators (LPD). SPDs are measured in milliseconds and LPDs are measured in seconds. Detonators can be chemical, mechanical, or electrical, the latter two being the most common. Explosive Ordnance Devices or EOD (hand grenades, naval mines etc.) mostly make use of mechanical detonators whilst the commercial use of explosives uses electrical detonators. Another form of detonator used in the commercial sector is that of the capped fuse which is a length of safety fuse to which an ordinary detonator has been crimped. Many detonators' primary (sensitive to heat, shock and friction) explosive is a material called ASA compound. This compound is formed from lead azide, lead styphnate and aluminium and is pressed into place above the base charge usually TNT or tetryl in military detonators and PETN in commercial detonators. Other materials such as DDNP (diazo dinitro phenol) are also used as the primary charge to reduce the amount of lead emitted into the atmosphere by mining and quarrying operations. Old detonators used mercury fulminate as the primary, and it was often mixed with potassium chlorate to yield better performance. Detonators vary in size and strength. The only detonators used for military applications are #6 and #8 blasting caps. There are so many different types of blasting caps with different primaries and sizes that it is nearly impossible to put a number to a detonator any more.

In a thermonuclear weapon a nuclear fission bomb is used as detonator to start nuclear fusion reactions. In fission bombs, pieces of plutonium or uranium are accelerated into a neutron source.

In situations where nanosecond accuracy is required, specifically in the implosion charges in nuclear weapons, exploding-bridgewire detonators are employed. They contain no explosive on their own, instead the shock wave is created by vaporizing a length of a thin wire by an electric discharge.

A new development is a slapper detonator, which uses thin plates accelerated by an electrically exploded wire or foil to deliver the initial shock. It is in use in some modern weapon systems. A variant of this concept is used in mining operations, when the foil is exploded by a laser pulse delivered to the foil by optical fiber.

Civilian use

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