FREE e-Newsletter
Important News - Hot Topics
Get them Now!

DrugTest 5000 - Draeger Safety Diagnostics Inc
In the past, roadside drug screening has been difficult because it involved the...

Exclusive Webinar!

Originally aired: June 17, 2014  ‚óŹ 2PM EST

View Webinar Archive Here

Integrated Law Enforcement Complements and Completes Law Enforcement Capabilities

Discover how the combination of intelligence analysis, lead generation, agency collaboration, and communications integration can help you uncover issues faster and take action sooner. Learn how innovative IBM law enforcement solutions can extend the capabilities within your organization to deal with new and emerging threats, improve officer safety, reduce criminal activity, and protect the public. 

Join IBM industry expert Stephen Dalzell and members from the MDPD, IT and homeland security departments of the Miami Dade police department to hear more!

Click here to view archive

 

Features

Things That Go Boom in the Night

Advanced techniques can help you detect all manner of explosives.

June 30, 2010  |  by Tim Dees - Also by this author

Computerized Tomography

One method used to identify explosives is a CT scan. Most people are now familiar with the term, even if the only place they've heard it was on a medical TV drama. The "CT" stands for computerized tomography, which is a method for generating a three-dimensional image from multiple 2-D X-ray images captured from multiple angles.

Modern CT scanners use multiple emitters to fire X-rays through an object to a sensor on the opposite side. The sensor records the gross structures it "sees" as well as the amount of energy received, giving an indication of the density of the material it passed through. The computer combines all of these images into one virtual object that appears on a computer display. The virtual object can be rotated on any axis and zoomed in or out to inspect details of interest.

Contraband objects with telltale shapes, like guns, are fairly easy to spot. The latest equipment stores data on densities of objects, both common and deadly, and uses X-ray diffraction to identify and display those in a telltale color. An operator at an airport or other high-threat location can pay closer attention to a container colored in red and determine whether it's plastic explosive or cold cream.

There are several limitations to CT as an explosives detector. The software that flags an explosive may give a false positive alert on something innocuous, like a child's Play-Doh. CT scanners are large-typically, the size of a small truck-and expensive. They're a chokepoint for any venue that has to process a lot of people or items in a short time.

The weakest link is the operator. Even when operators are rotated every 20 minutes or more frequently, fatigue causes them to miss objects that a fresher eye might see immediately. Watching a video display of wireframe images of everyday objects gets boring very quickly, and even the most conscientious employee's mind wanders. When the one-in-a-thousand Bad Thing goes by, it's easy to not see it.

Sniffers

Not all explosives detectors rely on the sense of sight. Some called "sniffers" don't exactly rely on the sense of smell. Labeling an Ion Mobility Spectrometry (IMS) instrument as a "sniffer" might be blasphemy to an analytical chemist, but it's a lot easier to say.

Ions are atoms or molecules containing an unequal number of protons and electrons, so they have a positive or negative charge. In an IMS instrument typically used for explosives detection, a sample is heated to produce a vapor, which is then ionized by a radiation source such as 63Ni or 241Am (there's something similar in the smoke detectors in your house).

The ions move through a drift chamber and an electric field that causes them to separate by size, mass, and geometry. As the ions arrive at a detector at the far end of the drift chamber, those size, mass, and shape characteristics form a signature unique to the compound from whence they came. If the signature matches one the device is programmed to detect, like PETN, it sounds an alarm.

Smiths Detection is one of the largest manufacturers of IMS instruments for explosives detection, and you've probably seen their machines at airport security checkpoints. Typically, an operator uses a glorified coffee filter to swab luggage or some other suspicious item, and places it in a recess for analysis. More often than not, a green light comes on, and you're on your way. The magic described above happens that fast. IMS detectors don't have the operator fatigue problems of CT scanners, but they're still expensive and have limited throughput.

SpectraFluidics has developed a new detection technology that is a combination of Free-Surface microFluidics (FSF) and Surface-Enhanced Raman Spectroscopy (SERS). A key component is a consumable "microfluidic chip" exposed to ambient air around the sample. The fluid, the channels that contain it, and nanoparticles suspended in it are specific for the substances to be detected.

A Raman laser, which works by measuring activity on the surface exposed or excited by the laser, produces a profile that is compared to that of the target substance. The effect is a detector that can be either fixed or handheld and costs a fraction of an IMS instrument. The microfluidic chips are consumed in the analysis process. The company plans to ship its first operational units this year.

Tags: Chemical Agents, Car Bombs, Bomb Squads

Request more info about this product / service / company


Be the first to comment on this story





POLICE Magazine does not tolerate comments that include profanity, personal attacks or antisocial behavior (such as "spamming" or "trolling"). This and other inappropriate content or material will be removed. We reserve the right to block any user who violates this, including removing all content posted by that user.

Other Recent Stories

How to Use a Pole Camera to Clear an Attic
Known as perhaps the most dangerous "fatal funnel" in police work, police officers...
Police Product Test: Pelican Progear Vault Series iPad Case
The Pelican ProGear Vault Series cases for iPad Air and iPad Mini may be the right...

Get Your FREE Trial Issue and Win a Gift! Subscribe Today!
Yes! Please rush me my FREE TRIAL ISSUE of POLICE magazine and FREE Officer Survival Guide with tips and tactics to help me safely get out of 10 different situations.

Just fill in the form to the right and click the button to receive your FREE Trial Issue.

If POLICE does not satisfy you, just write "cancel" on the invoice and send it back. You'll pay nothing, and the FREE issue is yours to keep. If you enjoy POLICE, pay only $25 for a full one-year subscription (12 issues in all). Enjoy a savings of nearly 60% off the cover price!

Offer valid in US only. Outside U.S., click here.
It's easy! Just fill in the form below and click the red button to receive your FREE Trial Issue.
First Name:
Last Name:
Rank:
Agency:
Address:
City:
State:
  
Zip Code:
 
Country:
We respect your privacy. Please let us know if the address provided is your home, as your RANK / AGENCY will not be included on the mailing label.
E-mail Address:

Police Magazine