Positioning rays have the ability to 'hunt' mines buried deep underground

Scientists at the Lincoln Laboratory at the MIT Institute are developing a high-definition sound beam, capable of detecting mines buried deep underground from a safe distance. This new type of ray will use sound to find mine-like mines using its sound-locating system to hunt.

Scientists have built a prototype detector and tested this machine at the US Army's Cold Regions Research and Manufacturing Laboratory (CRREL), which has facilities for mine equipment. US military engineer in charge of New Hamphire. Scientists were able to detect metal mines and plastic mines, but they said that the new mine detection system would have to gain a significant increase in sound power before mine detectors can use it safely.(Plastic mines - in addition to metal nibs are all plastic, so searching with a detector will be difficult - can only be found at a depth of about 12 cm).

Mr. Robert W. Haupt, a Lincoln Laboratory technician, has taken initiatives on methods to detect and reduce a large number of residual minefields in countries experiencing war. According to calculations, about 26,000 people were killed or injured each year due to 60 to 70 million unexplored mines in 70

Lincoln lab scientists at MIT are developing a type of ultrasound that is capable of finding mines buried deep in the same way as bats hunt.(Photo: Jon Barron, MIT Lincoln Lab)

country in the world. These casualties included soldiers but mostly civilians, with half of them children under the age of 16, who passed through mines that had not been cleared after the war.

Many standard mine detection systems are currently only able to detect metals so they limit the types of mines or improper mines in some minefields . 'It is very necessary to have reliable methods, to quickly and accurately locate metal mines and plastic mines, unexploded shells and shooting shots like other mines,' he said. Haupt said.

Mr. Haupt and his lab partner Lincoln - Mr. Ken Rolt - developed a high-power sound generator that looks like a stop sign on which small vials are used to hold films. or medicine. This machine is called limited sound sequence and Mr. Haupt and Mr. Rolt have built one of the most powerful machines available today.

The sound sequence is made up of ceramic transducers - devices that emit a powerful narrow beam of sound with ultrasound frequencies. One meter away, the measured sound pressure level is 155 decibels - which has a greater sound power than a jet engine. Immediately after being outside the sound beam, the sound intensity will become smaller and almost completely lost.

By a process called self-demodulation , the air in front of the sound beam transforms the ultrasound into sounds that are heard at lower frequencies, sounding like tuning tones with a loud sound. Small tools made of two steel branches that, when knocked on, emit a single sound. Unlike ultrasound, low-frequency sounds can penetrate the ground, causing recognizable vibrations in a mine.

" Using ultrasound allows us to create a super-narrow beam with a high orientation, like a flashlight that emits sound, " said Haupt . He said that to do the same thing, a large number of ordinary speakers and loudspeakers are too heavy, take up too much space and consume so much energy that they are not practical. . In addition, they will deafen anyone in their hearing. 'By using narrow beams, we can' set 'sounds wherever we want and we can minimize the levels of sound outside the sound to avoid harming people. operate the machine or people nearby, ' he said.

Once the ' crashing ' cannon is buried in the ground, vibrations from mines, resonances from sound waves, will push up on the ground and can be measured remotely with a laser system called ' seismograph Doppler ' action . The sound chart of mines looks like a mountain range with sharp peaks compared to the manifestations of soil and rock around the mine, which is a horizontal line.

'It turns out that vibrating mines are completely different from anything else,' says Haupt. 'You can know which kind of mine is - and which country makes them - through the chart is unique to them.'

Mr. Haupt is currently working with Mr Oral Buyukozturk, a civil engineering professor at MIT, to build a system capable of detecting damages in cement piers from very far distances. .

Thanh Van