This probe allows researchers to identify the composition of a sample atom by atom, but also to precisely map the location of each atom.
The potential practical applications are numerous, from the development of new treatments against osteoporosis to the development of more robust landing gear.
“We’re not just playing Legos with atoms,” said the scientific director of the PolyAPT platform, Professor Oussama Moutanabbir, of the physics engineering department of Polytechnique Montréal. “If we want to understand the position of atoms, it’s not just for the (pleasure of) doing it, it’s really to understand the performance of a material and why it will degrade.”
The Invizo 6000 tomographic atom probe analyzes the atomic composition of a sample by removing its atoms one by one to generate a three-dimensional image of the object at an unprecedented level of detail. An integrated mass spectrometer identifies not only the nature of each atom, but also their isotopic form. The tool is so sensitive that it recognizes the smallest atoms, even those of hydrogen and lithium.
The instrument could help develop cutting-edge materials for applications in quantum information technologies; nanoelectronics; optoelectronics; energy conversion and storage; metal alloys for aerospace; biointegrated technologies; and biomaterials.
The technology also makes it possible to consider the design of new generations of semiconductors and quantum materials sensitive to atomic variations and impurities. The device finally opens the way to better knowledge of fine structures, such as those inside batteries or biological tissues such as bones.
The acquisition of such a sophisticated device, as you can imagine, did not happen by snapping your fingers. The process began seven years ago and eventually required a partnership between the University of Montreal, the École de Technologie Supérieure, McGill University and the University of Sherbrooke to raise the millions of dollars needed.
The samples the probe analyzes are about a thousand times smaller than a human hair. Cut into a needle shape, they are frozen at a temperature of -230 degrees Celsius and subjected to an intense electric field. The pulsations of a laser then “lift” the atoms to the surface so that they can be analyzed.
“These intense electric fields make the atoms on the surface ‘loose’,” explained Professor Mouttanabir. Then it takes a few hundred (laser) pulses to tear off the atom, and once the atom is torn off it will be propelled towards the detector.”
The time it takes for the atom to travel to the detector allows researchers to determine its mass and chemical identity. The location where the atom hits the detector makes it possible to calculate where it was on the surface of the sample.
The device has already produced results that ignite the imagination, such as this meteorite sample that Professor Mouttanabir and his colleagues analyzed.
“We discovered that the meteorite predates the creation of the solar system, so it is more than five billion years old,” said the researcher.
One of Professor Mouttanabir’s collaborators is working, in partnership with industry, to develop the next generation of X-ray scanners.
To spot cancers as early as possible, he said, we need highly effective detectors. And a key element of this efficiency is the homogeneity at the atomic scale of the materials used for X-ray examinations.
The new device, said Professor Mouttanabir, allows us to “see where the atoms are placed, and their position and distribution will dictate the performance of the detectors.” And if the material used is more uniform, fewer X-rays will be needed to obtain the same result, he said.
“It is also important for everything related to security,” added Professor Mouttanabir. Soon, in airports, we will have detectors (so efficient) that we will no longer need to empty our bags.”
The acquisition of this machine allows, in a way, Professor Mouttanabir to “close the loop”, whose scientific career was in some way launched by a blurry photo of an atom seen in a science book when he was very young.
“For me, it was a shock. Can we see an atom?, he said in conclusion. Then I was always fascinated by controlling the position of the atom. In all my laboratories, we want to create materials one atom at a time. We take bags of atoms, we shake them, and if we have the right conditions, the atoms will organize themselves and create something useful.”
