Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Slow motion: antiprotons unravel atoms

10.11.2008
Theories on atomic reactions are being tested in collision experiments using a very slow beam of antiprotons

Quantum mechanics makes it easy to describe hydrogen, the simplest atom, but bigger atoms are more complicated owing to interactions between their electrons. It is especially difficult to predict the dynamics of atomic reactions during a collision. Now a team including RIKEN researchers has shed more light on this problem by performing collision experiments with slow beams of particles called antiprotons (1).

The researchers, based at the CERN particle accelerator complex in Switzerland, bombarded helium atoms with antiprotons. There is particular demand to do this with very slow antiproton beams, because current theories may not be accurate for low-energy collisions.

“Ionization by an antiproton, a unique heavy negative particle, is in itself quite exotic,” explains RIKEN scientist Yasunori Yamazaki. “In addition to this, helium is one of the most important targets to study collision dynamics because it has two electrons with a strong correlation between them.”

At CERN, antiprotons are produced in a nuclear reaction which gives them very high energies measured in billions of electron volts. They are then collected in an AD (antiproton decelerator), cooled and decelerated, so that their energies are reduced to a few million electron volts.

Yamazaki and co-workers constructed a new ‘radio frequency quadrupole decelerator’ and a ‘multi-ring trap’ to reduce the antiproton energy further down to a fraction of an electron volt, before re-accelerating them to 3,000–25,000 electron volts. This corresponds to speeds around 6,000 meters per second—very slow in particle accelerator terms.

The researchers directed their beam of slow antiprotons onto a jet of helium and argon, and monitored the energies of ions created. Their results show that the new theoretical models of low energy reactions are working, as Yamazaki explains.

“The previous experimental data did not agree with any reasonable theories, so there were big discussions on whether we forgot to include some important effects,” he says. “The good news is that it looks like our understanding on the collision dynamics of a slow antiproton and helium atom is now within satisfactory levels.”

Yamazaki and co-workers plan to develop more sophisticated equipment in order to achieve even lower antiproton energies, and observe not only the ions created during collisions, but also the electrons ‘knocked off’ the atoms. At lower energies the antiproton may get trapped in an orbit of the target atom, creating an interesting ‘molecule’ called an antiprotonic atom. The data could even help scientists investigating the use of antiprotons in treating cancer.

Reference

1. Knudsen, H., Kristiansen, H.-P.E., Thomsen, H.D., Uggerhøj, U.I., Ichioka, T., Møller, S.P., Hunniford, C.A., McCullough, R.W., Charlton, M., Kuroda, Y., et al. Ionization of helium and argon by very slow antiproton impact. Physical Review Letters 101, 043201 (2008).

The corresponding author for this highlight is based at the RIKEN Atomic Physics Laboratory

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/578/
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht NUS engineers develop novel method for resolving spin texture of topological surface states using transport measurements
26.04.2018 | National University of Singapore

nachricht European particle-accelerator community publishes the first industry compendium
26.04.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>