Black and Smokeless Powders Technologies for Finding Bombs and the Bomb Makers (1998) / Chapter Skim
Currently Skimming:
2 Detection of Black and Smokeless Powder Devices
2 Detection of Black and Smokeless Powder Devices
Pages 38-55
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 38... ...
Reprinted, with permission, from the Federal Aviation Administration (FAA)
|
From page 39... ...
Portable x-ray detection systems and specially trained dogs are also used in responses to reports of suspicious packages or bomb threats. As mentioned in Chapter 1, however, the majority of the bombs that cause casualties or significant property damage each year in the United States explode in locations where detectors are unlikely to be deployed.]
|
From page 40... ...
These markers make the plastic and sheet explosives approximately one million times easier to detect with vapor detectors (Elias, 1991~.3 The Committee on Smokeless and Black Powder was asked (see Appendix B) to assess the feasibility and desirability of adding markers to black and smokeless powders to enhance the likelihood of detecting explosive devices that use these powders.
|
From page 41... ...
The portal scenario represents the classic detection problem in which a bomb must be detected with high reliability and a low false-alarm rate in the midst of a large volume of innocent items. In the suspicious package and bomb threat scenarios, attention is already directed to a specific item or area, and the challenge is to determine if that particular item or area contains a bomb.
|
From page 42... ...
The same terminology is used in this chapter as in that study. DETECTING IMPROVISED EXPLOSIVE DEVICES CONTAINING UNMARKED POWDERS Assessing the desirability of adding markers to black and smokeless powders requires an understanding of current capabilities for detecting devices that use unmarked powders.
|
From page 43... ...
DETECTION OF BLACK AND SMOKELESS POWDER DEVICES TABLE 2.1 Current Detection Techniques for Unmarked Powder Devices 43 Detection Scenario/ Technology Object Detected Comments Portal X-ray Container/device Effective, high throughput; not usable to screen for devices carried by people Metal detector Container/device Effective if device contains metal; can detect devices carried by people Vapor/particle Powder New technology aimed at detecting high explosives; capabilities for detecting powders not fully determined Package X-ray Metal detector Container/device Vapor/particle Powder Dogs Powder Bomb threat Dogs Powder Container/device Portable, lower-cost systems available for use by bomb squads; helpful in identifying presence of bomb, rendering safe, and providing evidence afterward Effective if device contains metal Lower-cost, portable systems under development; capabilities for detecting powders not fully determined Effective, though exact chemicals detected by dogs and their sensitivity to powders inside well-sealed devices are not well understood Uniquely effective owing to both high sensitivity and self-guided searching capability Of a minivan.6 Such machines could be used at a few high-risk locations where the portal scenario applies, but would be difficult to use in the package scenario and impossible for the bomb threat scenario. In the case of black and smokeless powder devices, the presence of a container simplifies the detection problem considerably.
|
From page 44... ...
Other factors that could limit the effectiveness of vapor-based detection systems for devices using black and smokeless powders are the low volatility of some powders and the enclosure of the powders within pipes or other containers. The vapor pressure of single-base smokeless powders, black powders, and black powder substitutes is much lower than that of other smokeless powders,9 and the amount of vapor expected to escape from a typical bomb container has not been established.
|
From page 45... ...
Suspicious Package Scenario Portable standard x-ray systems are currently used to examine suspicious packages. For example, a basic portable model that can fit in the trunk of a large car and costs on the order of $20,000 is capable of providing an image of a suspicious package in real time.l2 There are several benefits of using x-ray machines in the package scenario.
|
From page 46... ...
Beyond detection, x-ray equipment also provides useful information that can assist in render-safe procedures and evidence gathering, and this equipment, when combined with metal detectors in the portal scenario, seems to be sufficient. In the bomb threat scenario, no current technologies seem to be applicable other than a thorough search by people or dogs.
|
From page 47... ...
An ideal marker system also would allow remote interrogation of suspicious packages or vehicles. · Chemical and physical compatibility with black and smokeless powder.
|
From page 48... ...
The ideal marker would ensure that black or smokeless powder detection is straightforward and unambiguous, requiring little or no operator training or subjective evaluation. It would have sufficient signal strength (and/or background suppression)
|
From page 49... ...
However, the minimum amount of black powder, single-base smokeless powder, and composite propellant detectable by various detection technologies focused on powder, rather than devices, would be much lower if the powder contained an active vapor marker than if the powder were unmarked. Unlike detectors based on interrogation of powders by nuclear or x-ray radiation, vapor marker detection is applicable to all scenarios, including detection of explosives concealed on people.
|
From page 50... ...
Also, the isotope emits a pair of nearly isotropic gamma rays with energies of 1.2 MeV and 1.3 MeV that would simplify the technical requirements for detection equipment. An important issue for marking of powders, however, is that the half-life of this isotope is 5.3 years, distinctly shorter than the expected shelf life of smokeless and black powders.
|
From page 51... ...
When discussing the potential value and difficulties involved in adding markers to smokeless and black powders, it is important to focus on the situations in which current detection of unmarked powders is insufficient or costly. Such situations include detection in the bomb threat scenario of any powder-based device, particularly one containing black or single-base smokeless powder.
|
From page 52... ...
Accordingly, vapor markers would likely add little to detection capabilities for these devices in the portal scenario. In the suspicious package scenario, portable x-ray systems are considered effective in detecting the device containers, and dogs are considered effective in detecting black and smokeless powders in the devices.
|
From page 53... ...
Finding: Current x-ray systems are capable of detecting explosive devices containing black and smokeless powders and are effective when placed at a portal or when used in portable equipment to examine a suspicious package. Current x-ray technologies are not suitable for quickly screening large numbers of packages or for performing large-area searches.
|
From page 54... ...
Finding: Detection markers added to black and smokeless powders could assist in the detection of explosive devices in several situations: large-area searches, examination of suspicious packages, rapid and routine screening of large numbers of packages, and enhancement of canine ability to detect black and smokeless powder bombs. A detection marker's value to law enforcement for detecting explosive devices containing black and smokeless powder would depend on the properties of the added marker, such as its degree of detectability through a sealed pipe or layers of wrapping, and on the portability and cost of the associated detection equipment, as well as its range and sensitivity.
|
From page 55... ...
X-ray systems and dogs currently provide a strong capability for detecting bomb containers and unmarked black and smokeless powders in the scenarios considered by the committee, and most powder bombings currently take place at locations in which deployment of bomb detection systems is not practicable (see Table 1.4~. Therefore, the committee believes that the effectiveness of a marking program would be limited at the present time.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.