Subscribe options

Select your newsletters:


Please enter your email address:

@

News & Media

Latest ITER Newsline

  • A wide angle on progress

    Whether captured from the top of a crane or from a drone hovering at an altitude of a few dozen metres, the ITER site isalways spectacular. After almost seven y [...]

    Read more

  • Inside the arena

    A visit to the deep "well" where the ITER Tokamak assembly will begin next year begins with a journey underground ... through a maze of giant pillars, [...]

    Read more

  • 10,000 tonnes of magnets to cool

    In ITER, huge volumesof liquid helium will be circulated throughout a complex, five-kilometre network of pipes, pumps and valves to keep the 10,000-tonne magnet [...]

    Read more

  • Heaviest convoy yet

    The triple convoy that reached ITER on Thursday 13 April wasthe heaviest ever organized since the beginning of "highly exceptional" deliveries in Janu [...]

    Read more

  • Gouging the giant's eye

    On the side of the ITER bioshield that faces the main ITER office building, four large openings have been preserved to allow passage for the neutral beam inject [...]

    Read more

Of Interest

See archived articles

Fusion on the micro-scale

-Florian Aigner, Vienna University of Technology

Artur Golczewski from the Vienna University of Technology mounting the high precision scale. Photos (2): Vienna University of Technology (Click to view larger version...)
Artur Golczewski from the Vienna University of Technology mounting the high precision scale. Photos (2): Vienna University of Technology
One of the world's most accurate scales is currently being used for fusion research at the Institute of Applied Physics at the Vienna University of Technology (VUT). A research group led by Professor Aumayr reproduces the physical conditions on the fusion reactor's walls in its experiments. In the laboratory, the interaction between high-energy ions and solid surfaces can be studied much more precisely than it ever could inside an actual fusion reactor.

A key tool for this research is the quartz crystal microbalance, which was developed by Professor Michael Schmid from the VUT. A small piece of the surface material, which is supposed to be used in the fusion reactor, is irradiated with high-energy particle beams, and tiny changes of its weight are measured with great accuracy. This way, one can determine whether the particle bombardment knocks atoms out of the surface, reducing the mass of the specimen, or whether the incident particles are instead implanted into the material, thereby increasing its mass.

The vacuum chamber in which the high-precision measurements with the quartz crystal scale are being performed. (Click to view larger version...)
The vacuum chamber in which the high-precision measurements with the quartz crystal scale are being performed.
The microscale developed at VUT is one of the world's most accurate scales. "Mass changes of as little as one billionth of a gram can be measured," says Katharina Dobes, research assistant at the Institute of Applied Physics. Even if the particle bombardment only removes one single atomic layer from the surface, the resulting change in mass can still be evaluated.
The fundamental idea behind this incredible precision is rather simple: a quartz crystal is vibrated and its resonance frequency is measured. This frequency depends very sensitively on the crystal's mass. If the crystal surface is coated with the material under investigation and then hit by particles, the changing resonance frequency of the crystal can be translated in a mass change of the material on top of it. That way it is possible to determine the effect the particle bombardment has on the surface.

The application of this measuring device is not restricted to fusion research. "In particle-surface interactions, there are many quantum mechanical phenomena which play a crucial role. In this field, many interesting fundamental questions are yet to be answered," Professor Aumayr believes.


return to the latest published articles