Spotting carboot bombers

Improvised explosive devices are the weapon of choice for suicide bombers and have been a major cause of military and civilian casualties in Iraq, Afghanistan, and elsewhere in the world. Now, a group in engineering at the University of Michigan have developed a novel approach to detection of such devices that might allow security forces to intervene in a situation before a device is detected.

A team of undergraduate students at Michigan have developed a palm-sized metal detector based on a magnetometer explains team member Ashwin Lalendran who graduated in May 2009.

The device could be hidden in rubbish bins, under tables or in flowerpots, that are linked together using a wireless sensor network connected to a peripatetic command centre. The inexpensive low-power devices have a long transmission range and outperform all other devices on the market according to Nilton Renno, the team’s supervisor.

“We built it entirely in-house – the hardware and the software,”
explains Lalendran. “Our sensors are small, flexible to deploy, inexpensive and scalable. It’s extremely novel technology.”

The technology has already earned recognition with the Michigan team recently winning a competition sponsored by the US Air Force in conjunction with Ohio State University. The Air Force Research Laboratory at Wright Patterson Air Force Base and other bases across the US sponsor similar contests on a regular basis with the aim of getting a rapid technological reaction to ongoing issues that can be highly innovative.

The team has tested its system in Dayton, Ohio, at a mock outdoor sale event – a simulated carboot sale – secreting detectors across the site.
The organisers then hid simulated explosive devices among the crowd in backpacks and handbags and among the goods “on sale”.

“We had an excellent turnout in technology,” Tenning said. “Regardless of the competition results, often successful ideas from each student team can be combined into a product which is then realized for Department of Defence use in the future.”

Their success demonstrated sound engineering skills and a lot of imagination to the solution of an extremely difficult real-world problem, said Bruce Block, an engineer in the Space Physics Research Laboratory, who worked with the team. He adds that, “they worked well together and never gave up when the going got rough.” The students will continue to work on this project through the summer.

Team member Michael Shin discussing the development of a wireless network for detecting suicide bombers (Credit: UMich)

Podcast from The University of Michigan

13.73 Billion years BCE

Science doesn’t have a lot to say about what happened before the Big Bang, but researchers have now developed microwave detectors that will let them take a look at the first trillionth of a trillionth of a trillionth of a second after that primordial cosmic event.

A collaboration between scientists at the National Institute of Standards and Technology (NIST), Princeton University, the University of Colorado at Boulder, and the University of Chicago has yielded super-sensitive microwave detectors that were revealed at the American Physical Society (APS) April meeting held in Denver during May.

Cosmic microwave temperature fluctuations fill the sky and are an echo of the first moment after the Big Bang (Credit: NASA/WMAP Science Team)

Cosmic microwave temperature fluctuations fill the sky and are an echo of the first moment after the Big Bang (Credit: NASA/WMAP Science Team)

The cosmic microwave background (CMB) is often referred to as the afterglow of creation. This remnant, or echo of the Big Bang fills the universe and various projects have obtained snapshots of the CMB stretching back closer and closer to the Big Bang. The new project will use a large array of the sensors mounted on a telescope mounted in the Chilean desert. They will look for subtle fingerprints of the CMB from primordial gravitational waves, ripples in the fabric of the spacetime continuum. Theory has it that these waves will have left an imprint on the direction of the CMB’s electric field, called the B-mode polarization.

This is one of the great measurement challenges facing the scientific community over the next twenty years, and one of the most exciting ones as well, says Kent Irwin, the NIST physicist leading the project.

Prototype NIST detector that will be used to spot signature of rapid inflation immediately after the Big Bang. (Credit: NIST)

Prototype NIST detector that will be used to spot signature of rapid inflation immediately after the Big Bang. (Credit: NIST)

If found, these waves would be the clearest evidence yet in support of the inflation theory, which suggests that all of the currently observable universe expanded rapidly (within the first tiny fraction of a second) from a subatomic volume, leaving in its wake the telltale cosmic background of gravitational waves.

The B-mode polarization is the most significant piece of evidence related to inflation that has yet to be observed, explained NIST’s Ki Won Yoon, at the APS meeting. A detection of primordial gravitational waves through CMB polarization would go a long way toward putting the inflation theory on firm ground.

These types of experiments can only be done by treating the universe as a whole as a cosmic laboratory. The particles and electromagnetic fields that exist immediately after the Big Bang are billions of times more energetic than those available even with the most powerful particle colliders on Earth today. On this energy scale, three of the fundamental forces of nature but excluding gravity, are predicted to merge into a single unified force.

At the energy scale at which inflation occurred, which is the GUT or Grand Unified Theory energy scale, only 3 out of the 4 fundamental forces are predicted to merge into a single unified force – electromagnetism, the strong nuclear force, and the weak nuclear force, Irwin told Spotlight.

The final force of nature, gravity, is not predicted to merge with the other three until a much higher energy scale referred to as the Planck scale, which would have occurred before inflation, and would not have been related to the primordial gravity waves. A theory that correctly incorporates gravity into a unified field is humorously referred to as a TOE or Theory of Everything, he adds.

Further reading

APS April 2009 Meeting

National Institute of Standards and Technology homepage

Suggested searches

Big Bang
cosmic microwave background

Lucky break fixes astronomers’ blurred vision

A new method for getting a clear astronomical view of the night sky has been developed by UK astronomers. The technique cancels out the blurring effects of the Earth’s atmosphere and could allow astronomers to obtain Hubble-quality images without the need for reliance on an expensive space-based telescope.

Craig Mackay and his colleagues at the University of Cambridge have developed their technique using a charge-coupled device detector built by E2V Technologies of Chelmsford, a sophisticated relative of the image chip found in digital cameras and camera phones. However, their CCD can take high-resolution pictures of the night sky one frame after another at high speed. A computer program developed by Mackay’s team then picks out only those images with the least noise and adds them together to cancel out any readout noise. At the same time, image distortion caused by the atmosphere is also cancelled out in the process.

John Baldwin

John Baldwin

Mackay and his team in the Institute of Astronomy and John Baldwin of the Cavendish Laboratory worked together with the aim of allowing astronomers to map the Universe’s dark matter. Cosmologists believe dark matter accounts for 90 percent of the mass of the Universe but remains an enigma because it is invisible to conventional telescopes. Its existence is only inferred on the basis of the expansion of the Universe as measured using the red-shifts of bright objects in the cosmos such as stars, galaxies and quasars as they race away from Earth.

Understanding the distribution of dark matter properly will, however, provide scientists with a better understanding of how the Universe evolved from the Big Bang and perhaps tell us how it will evolve in the distant future. It could answer one of the biggest questions facing cosmologists – will the Universe expand forever, or will it ultimately end in a Big Crunch as gravity causes it to collapse into a singularity.

Craig Mackay

Craig Mackay

This new camera and the image selection method we call ‘Lucky Imaging’ will revolutionise astronomical image quality obtainable from the ground, says Mackay. There are currently many observing programmes that need to cover wide areas of the sky, something the Hubble Space Telescope cannot do. This method will now allow wide field imaging with a level of quality only achievable with the Hubble Space Telescope, he adds.

Animated Lucky (Original images Courtesy of AST/Cambridge)

The Cambridge technique will allow astronomers to measure how images of distant galaxies are distorted by invisible dark matter. This is the first time we may have a technique that will allow the tracing of dark matter throughout the Universe to be tackled properly, says Mackay.

Still frame from animated Lucky (Original images Courtesy of AST/Cambridge)

Still frame from animated Lucky (Original images Courtesy of AST/Cambridge)

The method will give us much more accurate information and allow us to work on much fainter galaxies then we can at present from ground, Mackay told Spotlight. By looking at the change in scale of the dark matter we can work out how these mass distributions are evolving in time. The researchers do this by looking at the way that distant galaxies are distorted in comparison with the way that closer galaxies are affected. The distortions of the most distant galaxies are caused by all the dark matter fluctuations as the light travels across the Universe whereas the distortions of the near galaxies are only caused by the distortions of closer dark matter structures. Provided we have enough information of good enough quality then we should be able to work out the way in which these dark matter structures change, if indeed they do change, with red-shift, adds Mackay.

The team is already planning to improve on the technique to image the sky more quickly and efficiently. The current CCD cannot cover a larger part of the sky. If we are to cover reasonably large areas of sky we need to use an array of these detectors, Mackay revealed to us. It is simply by having large numbers (perhaps an array of 100, all working in parallel, each with their own moments of Lucky imaging quality) that the proposed instrument is more powerful.

Further reading

Professor John Baldwin

Lucky Imaging website

Suggested searches

dark matter