Control charge detonators

The functional components of a bomb are a control system, detonator, booster, and a main charge. Such threats can often be recognized from their shape. These can be viewed as bulk detection issues, historically addressed by imaging techniques such as sight or touch. Other threats may take no particular physical form and can only be recognized by their chemical composition. These are often trace detection issues, historically detected by the sense of taste or smell. 

Drone Charges. These are used where it is desired to load the max wt of expl in min time in a boat or other carrier which is to be run up to die firing point by remote control and detonated en masse Ref NDRC Summary Rept of Div 8, Vol 1 (1946), 62... 

Donor, acceptor, and control charges are placed along the same axis on a 700x 700x100 mm steel plate (Figure 2.32). When the distance between the donor and the acceptor charge is adjusted, the initiation of the donor charge is performed by a standard detonator. 

The efficacy of transmission of detonation can be estimated on the basis of the completion of detonation of the control charge placed immediately after the acceptor charge and on the basis of the traces left on the steel plate. When the complete detonation of the acceptor charge occurs, the control charge is detonating too. In the absence of detonation, it is only thrown away or damaged. 

Because of the extreme importance of regularity and freedom from failure which must characterise safety fuse, detailed and exhaustive tests must be carried out on the product. Certain controls are obvious, namely, measurement of powder charge and of burning speed, both before and after immersion in water. Other tests usually carried out include resistance to cracking on flexing at low temperatures round a mandrel, coil tests in which the fuse is bunched into flat or complex coils and freedom from failure after immersion in water is determined. New types of fuse are usually tested to indicate the amount of smoke produced and also to determine the adequacy of the end spit. The end spit is the projection of particles of burning powder from a cut end and is of importance because it provides the mechanism which enables the fuse to ignite a detonator. 

A bomb can be considered to contain four functional blocks, namely, a control system, a detonator, a booster, and a main charge. Although a simple ignition fuse can be used as a control system and timing device, the control system is usually more mechanical or electrical in nature. The detection of control systems may be visual, or by magnetometry, or by X-ray. It must be remembered that many of the items involved in the ignition system, that is, clockwork, batteries, or electronic circuitry, are commonplace in ordinary items, such as cameras, mobile telephones, and personal stereos, and are not unique indicators of the presence of a bomb. In fact, it is the presence of explosives that is the key indicator of a bomb. 

Explosives are classed as primary or secondary. Typically, a small quantity of a primary explosive would be used in a detonator (known colloquially as a cap ), whereas larger quantities of secondary explosives are used in the booster and the main charge of a device. This collection of explosives is known as an explosive train in which a signal (mechanical, thermal, or electrical) from the control system is converted first into a small explosive shock from the detonator, which in turn initiates a more powerful explosion in the booster, which amplifies the shock into the main charge. 

Air Gap Sensitiveness to Detonation (and Explosion). It is a term which has been applied to the maximum distance of the consistent propagation of detonation by influence from a primer charge across an air gap to a receptor charge. The air-gap test for sensitiveness has been used for many years as a control test for dynamites and other commercial expls. 

Mine. An enclosed explosive or chemical charge designed to be placed in position so that it detonates when its target touches or moves near it, or when touched by remote control. General types are Land Mine and Underwater Mine. The term mine may also mean an explosive charge placed in a subterranean tunnel under a fortification (Ref 40a, pp 99 142)... 

Graphite-filled PVC provides resilient coatings which can leak off dangerous electrostatic charges from explosives propellants (Ref 3) Remote control sites for handling explosives capable of withstanding detonations of up to 10 lbs TNT are described (Ref 4)... 

The placement of the initiator should be well controlled because bad comer turning ability of the detonation wave in some explosives may otherwise cause partial decomposition of different parts of the charge. 

When controlled explosives are used, the most common method is to place carefully measured charges in shallow shot holes a few inches in diameter drilled from a truck-mounted drill. These charges are then detonated to produce the sound waves needed. In less accessible areas, a portable drill may be used and, in certain environmentally sensitive areas, the charges may be mounted on stakes above the ground to minimize plant disturbance. 

Cohen and Price s model was applied to several HMX propint formulations with the results shown in Figs 6, 7 and 8. The model information is represented by the solid line plot 58) D. Price A.R. Clairmont, Jr, Explosive Behavior of Simplified Propellant Models , Comb Flame 29, 87-93 (1977) CA 87, 55269 (1977) [The objective of the study was to determine deton vel (D), detonability and shock sensy as functions of loading d (p0) and (critical) charge diameter (dc) for a model proplnt compn contg AP/Al/wax/HMX (50/15/ 15/20%). From the data the authors conclude that (1) D varies directly (or linearly) with po (2) dc increases with increasing p0, (3) deton is diffusion controlled, (4) the proplnt cannot be dead-pressed (it will always detonate), (5) the proplnt is a group 2 expl, and (6) addn of 20% HMX to a proplnt model without expin at 55% theoretical max d lowers the relative Eyring reaction time (to deton) from 1.0 to 0.45 units]... 

The initiator in this instance is a length of detonating cord, donor and acceptor charges are both PETN, and the body is type 303S stainless steel with the bulkhead 0.075 " thick. This TBI was developed to initiate solid proplnt rocket motors that are used during stage separation to control the ullage in the main proplnt tanks and to provide retro thrust. The TBI ends are sealed so that the TBI will better withstand the temp environment (Ref 2)... 

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