Helium atoms sent by nozzle may light way for new imaging approach

Jul 26, 2006

A newly devised nozzle fitted with a pinhole-sized capillary has allowed researchers to distribute helium atoms with X-ray-like waves on randomly shaped surfaces. The technique could power the development of a new microscope for nanotechnology, allowing for a non-invasive, high-resolution approach to studying both organic and inorganic materials.

All that is needed is a camera-like detector, which is now being pursued, to quickly capture images that offer nanometer resolution, said principal investigator Stephen Kevan, a physics professor at the University of Oregon. If successful, he said, the approach would build on advances already achieved with emerging X-ray-diffraction techniques.

Reporting in the July 7 issue of Physical Review Letters, Kevan's four-member team described how they sent continuous beams of helium atoms and hydrogen molecules precisely onto material with irregular surfaces and measured the speckle diffraction pattern as the wave-like atoms scattered from the surface.

The research, funded by the National Science Foundation and U.S. Department of Education, was the first to capture speckle diffraction patterns using atomic de Broglie waves. The Nobel Prize in physics went to France's Louis de Broglie in 1929 for his work on the properties of matter waves.

"The approach of using the wave nature of atoms goes back 100 years to the founding of quantum mechanics," Kevan said. "Our goal is to make atomic de Broglie waves that have very smooth wave fronts, as in the case in laser light. Usually atom sources do not provide wave fronts that are aligned coherently, or nice and orderly."

The nozzle used in the experiments is similar to one on a garden hose. However, it utilizes a micron-sized glass capillary, borrowed from patch-clamp technology used in neuroscience. The capillary, smaller than a human hair, provides very small but bright-source atoms that can then be scattered from a surface. This distribution of scattered atoms is measured with high resolution using a field ionization detector.

The helium atoms advance with de Broglie wavelengths similar to X-rays, but are neutral and non-damaging to the surface involved. Kevan's team was able to measure single-slit diffraction patterns as well as speckle patterns made on an irregularly shaped object.

Getting a timely image remains the big obstacle, Kevan said. Images of diffraction patterns produced pixel-by-pixel in the study required hours to accumulate and suffer from thermal stability limitations of the equipment. "We'd like to measure the speckle diffraction patterns in seconds, not a day," he said.

"Given its simplicity, relative low cost, continuous availability, and the unit probability for helium scattering from surfaces, our source will be very competitive in some applications," Kevan and colleagues wrote.

"This atom optical experiment would benefit from developing an 'atom camera,' that would measure the entire speckle pattern in one exposure," they wrote.

Source: University of Oregon

Explore further: A 'movie' of ultrafast rotating molecules at a hundred billion per second

Related Stories

Physicists observe magnetic 'devil's staircase'

Jun 24, 2015

(Phys.org)—Many hiking trails feature a "devil's staircase"—a set of steps that are often steep and difficult to climb. The devil's staircase is also the name of a mathematical function whose graph exhibits ...

3D potential through laser annihilation

Jun 16, 2015

Whether in the pages of H.G. Wells, the serial adventures of Flash Gordon, or that epic science fiction saga that is Star Wars, the appearance of laser beams—or rays or phasers or blasters—ultimately ...

Building a better microscope to see at the atomic level

Jun 01, 2015

One of the more famous images in biology is known as "Photo 51," an image of DNA that chemist Rosalind Franklin and Raymond Gosling created in 1952 by shooting X-rays through fibers of DNA and analyzing the ...

Recommended for you

Extreme lab at European X-ray laser XFEL is a go

Jul 02, 2015

The Helmholtz Senate has given the green light for the Association's involvement in the Helmholtz International Beamline (HIB), a new kind of experimentation station at the X-ray laser European XFEL in Hamburg, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.