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: Finding faster-than-light particles by weighing them

add to favorites email to friend print save as pdf

Related Stories

Shortcut to protein portraits

Dec 16, 2014

All living organisms, from bacteria to humans, rely on proteins to perform their vital functions. How these proteins accomplish their tasks depends on their structure. Researchers from the Paul Scherrer Institute ...

Why I'm proud to be a crystallographer

Dec 10, 2014

This year I have learnt more that it is probably healthy to know about crystal structures. I've learnt how you can turn a rabbit green with a protein, read up on French military history and marvelled at how a crystal structure can destroy itself. ...

A first-of-its-kind discovery with an X-ray laser

Dec 05, 2014

A research team led by physicists at the University of Wisconsin-Milwaukee (UWM) has proven a method that makes it possible to find the atomic structure of proteins in action by producing "snapshots" of them ...

Recommended for you

Finding faster-than-light particles by weighing them

Dec 26, 2014

In a new paper accepted by the journal Astroparticle Physics, Robert Ehrlich, a recently retired physicist from George Mason University, claims that the neutrino is very likely a tachyon or faster-than-light par ...

Controlling core switching in Pac-man disks

Dec 24, 2014

Magnetic vortices in thin films can encode information in the perpendicular magnetization pointing up or down relative to the vortex core. These binary states could be useful for non-volatile data storage ...

Atoms queue up for quantum computer networks

Dec 24, 2014

In order to develop future quantum computer networks, it is necessary to hold a known number of atoms and read them without them disappearing. To do this, researchers from the Niels Bohr Institute have developed ...

New video supports radiation dosimetry audits

Dec 23, 2014

The National Physical Laboratory (NPL), working with the National Radiotherapy Trials Quality Assurance Group, has produced a video guideĀ to support physicists participating in radiation dosimetry audits.

Acoustic tweezers manipulate cell-to-cell contact

Dec 22, 2014

Sound waves can precisely position groups of cells for study without the danger of changing or damaging the cells, according to a team of Penn State researchers who are using surface acoustic waves to manipulate ...

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.