Detonator
A detonator is used to trigger bombs, shaped charges and other forms of explosive device. Detonators are often attached to a timer to ensure that the explosion takes place at the desired time, or when the person laying the explosives has reached a safe distance from the blast. Detonators can be chemical, mechanical, or a combination. Many detonators' primary (sensitive to heat and shock) explosive is a material called tetryl.
In a nuclear weapon a nuclear fission bomb is used as detonator to start nuclear fusion reactions.
See also
ja:雷管