RP EBW Detonator. P/N . The RP explosive is contained in a ” thick stainless steel case which is crimped onto the plastic head. OPEN ACCESS. A view on the functioning mechanism of EBW detonators -part 1: electrical characterisation. To cite this article: E A Lee et al J. Phys.: Conf. Exploding Bridgewire (EBW) Detonators are in widespread use and have proven reliability and performance characteristics. Since their invention there have.
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This page was last edited on 31 Octoberat The resulting shock and heat initiate the high explosive. The extremely short rise times are usually achieved by discharging a low- inductancehigh-capacitance, high-voltage capacitor e. This in turn has led to the calculation of the energy efficiency of the fireset bridgewire system and an estimate of the energy delivered post bridgewire burst.
Primary explosives such as lead azide are very sensitive to static electricity, radio frequency, shock, etc. The flux compression generator is one alternative to capacitors.
EBWs have found uses outside nuclear weapons, such as the Titan IV safety conscious applications where stray electrical currents might detonate normal blasting caps, and applications requiring very precise timing for multiple point commercial blasting in mines or quarries. If the current rise rate is lower, the bridge may burn, perhaps causing deflagration of the PETN pellet, but it will not cause detonation.
An EBW has two main parts: EBWs were developed as a means of detonating multiple explosive charges simultaneously, mainly for use in plutonium-based nuclear weapons in which a plutonium core called a pit is compressed very rapidly.
Booster charge circled in green. In the US, due to their common use in nuclear weapons, these devices are subject to the nuclear control authorities in every state, according to the Guidelines for the Export of Nuclear Material, Equipment and Technology. Two EBW arms circled in light green. The precise timing of EBWs is achieved by the detonator using direct physical effects of the vaporized bridgewire to initiate detonation in the detonator’s booster charge.
Consequently, the detonators must have very precise timing. However, they require a bulky power source for the current surges required.
Content from this work may be used under the terms of the Creative Commons Attribution 3. When fired, it creates a strong electromagnetic pulsewhich is inductively coupled into one or more secondary coils connected to the bridge wires or slapper foils.
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A view on the functioning mechanism of EBW detonators -part 1: electrical characterisation
Buy this article in print. Low- impedance capacitors and low-impedance coaxial cables are required to achieve the necessary current rise rate. During this phase the electrical resistance of the bridgewire assembly rises. Closeup with EBW highlighted. Imprecise contact between the bridgewire and the primary explosive changes how quickly the explosive is heated up, and minor electrical variations in the wire or leads will change how quickly it heats up as well.
This paper is the first of three characterising the initiation of PETN in an exploding bridgewire detonator to understand the underlying mechanism. Closeup of a detonator set.
E A Lee et al J. The heating process typically takes milliseconds to tens of milliseconds to complete and initiate detonation in the primary explosive. Their use is limited by the thermal stability range of PETN.
Retrieved from ” https: A deetonator energy density capacitor equivalent to a compression generator would be roughly the size of a soda can. Views Read Edit View history. This is roughly 1, to 10, times longer and less precise than the EBW electrical vaporization. However, there is still not a universally accepted mechanism. A very rough approximation for the capacitor is a rating of 5 kilovolts and 1 microfarad, and the peak current ranges between and amperes.
The measurement of current, time to deonator burst and the transient voltage across the bridgewire at burst have enabled the determination of the energy used in bursting the bridgewire. Since their invention there have been numerous studies to identify the mechanism by which the exploding bridgewire ebs the explosive. This is sufficiently precise for very low tolerance applications such as nuclear weapon explosive lenses.
The EBW is the Y-shaped device with two wires coming in at angles along the surface. When the wire is connected across this voltage, the resulting high current melts and then vaporizes the wire in a few microseconds.
Detonators without such booster are called initial pressing detonators IP detonators. This accounts for the heavy cables seen in photos of the Trinity ” Gadget “; high voltage cable requires good insulation and they had to deliver a large current with little voltage drop, lest the EBW dbw achieve the phase transition quickly enough.
Any further distribution of this work must maintain attribution to the author s and the title of the work, journal citation and DOI. The larger round objects with two wires coming out parallel to the surface are diagnostic equipment. The heating rate is high enough that the liquid metal has no time to flow away, and heats further until it vaporizes.
During initiation, the wire heats with the passing current until melting point is reached.
Exploding-bridgewire detonator – Wikipedia
Given a sufficiently high and well known amount of electric current and voltage, the timing of the bridgewire vaporization is both extremely short a detonahor microseconds and extremely precise and predictable standard deviation of time to detonate as low as a few tens of nanoseconds. The most common commercial wire size is 0.