Page 8
www.us-tech.com
Bombs and Nuclear Threats Continued from page 1
PCB Prototypes & Medium Volume
Get the best Price & Service for special technology Proto‘s & volume PCB quantities
Flex PCB Prototypes Favourable pricing
FREE Stencil with every PCB-POOL® prototype order
For information, please call at
916 241 9062
www.pcb-pool.com
Terminal. Cargo scanning today relies pri-
marily on high-powered X-rays, which provide a 2D projection of ob- ject shapes inside containers. Dense objects, which could harbor nuclear threats or contraband, are further in- vestigated by opening the container. Opening and inspecting each suspi- cious container can take hours and is dangerous. Passport’s cargo scanners, on
the other hand, offer precision scan- ning in minutes, without ever open- ing a container, states Bertozzi, now Passport’s scientific advisor and a member of its board of directors. “In about 30 seconds, we can scan a con- tainer and provide a 3D map of the materials inside. This information clears the container or alerts inspec- tors to a region that needs to be ex- amined more carefully. In another 15 seconds, the scanner will tell you whether there’s an actinide there. In another half a minute, we can tell you what actinide it is, and if it’s a bomb,” he says. The company’s handheld sys-
tem, called SmartShield, is a net- work of small gamma-radiation de- tectors, about the size of a deck of cards, that collects radiation data in real-time and wirelessly connects to smartphones. Typically, law enforce- ment and first responders wear the detectors on their belts and carry the phones, while walking around and collecting data on background radia- tion. If a detector identifies gamma radiation, it sends an alert to all oth- er smartphones in the network, as well as a central command station, and displays the radiation’s GPS co- ordinates.
SmartShield was tested at last
year’s NASCAR race in New Hamp- shire, this year’s NCAA Final Four Men’s Basketball Championship in Texas, and other major events in the U.S.
Fingerprinting Actinides The SmartScan facility at the
Port of Boston is a tunnel about 176 feet long, resembling a drive-through car wash. Trucks carrying land and sea cargo containers are pulled through slowly on a conveyer belt, and scanned by a massive scanner attached to the tunnel’s entrance. This scanner combines conventional high-resolution X-rays and other passive radiation detection methods with scanning techniques pioneered by Bertozzi at the MIT Laboratory for Nuclear Science and by Passport. As a truck passes through the
scanner, Passport’s custom EZ 3-D scanning method generates 3D im- ages of a material based on the effec- tive atomic number, called “effective Z,” which could indicate explosives. To do so, an electron beam produces photons that shoot into the material. The electrons of atoms in the materi- al scatter these photons. The system measures the photon signals to de- termine any anomalies. Photon sig- nals for high-Z materials such as ac- tinides, for instance, are about 10 times higher than signals from low-Z materials, like those found in com- mon metals. “Because these photon signals are huge and prolific, we can tell you where in the container you
Advanced Screening for
have materials that are high effec- tive Z,” Bertozzi says. But some of these signals are difficult to differen- tiate, so if suspicious materials are present, the system automatically conducts refined, secondary scans. The first technique is Prompt
Neutrons from Photofission (PNPF), developed by Bertozzi at MIT in the 1960s. A photon beam causes fission in the material’s actinide nuclei, which release measurable amounts of neutrons. If the neutrons are pro- duced over a certain threshold of en- ergy, they are from an actinide. Then the system uses another technique developed by Bertozzi, called nuclear resonance fluorescence (NRF), where the photon beam excites the nuclei, causing them to emit gamma rays at distinct energy levels. Measuring those energy levels gives the “finger- print” of the actinide. “We can tell you if it’s, say, uranium-235, urani- um-238, oxygen-17, or carbon-12, be- cause they all have different signals,” Bertozzi says. Drugs and alcohol have specific
“fingerprints” too, as do materials such as salt and chlorine, so the scanner is helpful for detecting con- traband. A scanner, for instance, could detect chlorine, sometimes used to make methamphetamine, in a truck full of clothing. Now, the U.K. is seeking the
systems to look for items such as un- taxed tobacco being smuggled across the border, while other countries are looking for the systems to scan for drugs and alcohol. “It serves a securi- ty need, but it also satisfies general customs needs,” says Passport’s CEO, president, and co-founder Robert Ledoux. “That has made it commercially viable.” Passport’s SmartShield detec-
tors use standard photon-detection technology to detect gamma rays. But the innovation comes from the network, which offers numerous ben- efits, Ledoux says. Working together, the scanners can quickly triangulate the location of a threat. Constantly updated radiation data, from multi- ple detectors being carried around an area, also makes the system as a whole more sensitive. “With each passing sweep, it can better separate naturally occurring radiation in, say, building materials from hazardous nuclear materials,” Ledoux says.
Coming together at MIT In the mid-1990s, Bertozzi tried
bringing his MIT-invented NRF scanning technology to a company that was trying to commercialize baggage-scanning technologies in U.S. airports. Despite successful tests, the company decided the tech- nology was too expensive to scale, es- pecially since airplane bombings weren’t necessarily considered a ma- jor threat. “But then the world changed
with 9/11,” Ledoux says. Suddenly, the newly minted Department of Homeland Security wanted all bag- gage at airports and every cargo unit at the U.S. border scanned for explo- sives. X-rays and CT scans were used for luggage, but no quick, accurate scanning techniques existed for cargo containers. “It’s difficult to detect ex- plosives in a small package. Imagine having a 40-foot container filled with thousands of pounds of things, whip-
Continued on page 40
August, 2016
PCB-POOL® is a registered trademark of Beta LAYOUT GmbH
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88