Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UC Riverside physicists discover new way to produce antimatter-containing atom

12.07.2011
New method allows positronium to be produced for the first time at a wide range of temperatures and in a controllable way

Physicists at the University of California, Riverside report that they have discovered a new way to create positronium, an exotic and short-lived atom that could help answer what happened to antimatter in the universe, why nature favored matter over antimatter at the universe's creation.

Positronium is made up of an electron and its antimatter twin, the positron. It has applications in developing more accurate Positron Emission Tomography or PET scans and in fundamental physics research.

Recently, antimatter made headlines when scientists at CERN, the European Organisation for Nuclear Research, trapped antihydrogen atoms for more than 15 minutes. Until then, the presence of antiatoms was recorded for only fractions of a second.

In the lab at UC Riverside, the physicists first irradiated samples of silicon with laser light. Next they implanted positrons on the surface of the silicon. They found that the laser light frees up silicon electrons that then bind with the positrons to make positronium.

"With this method, a substantial amount of positronium can be produced in a wide temperature range and in a very controllable way," said David Cassidy, an assistant project scientist in the Department of Physics and Astronomy, who performed the research along with colleagues. "Other methods of producing positronium from surfaces require heating the samples to very high temperatures. Our method, on the other hand, works at almost any temperature – including very low temperatures."

Cassidy explained that when positrons are implanted into materials, they can sometimes get stuck on the surface, where they will quickly find electrons and annihilate.

"In this work, we show that irradiating the surface with a laser just before the positrons arrive produces electrons that, ironically, help the positrons to leave the surface and avoid annihilation," said Allen Mills, a professor of physics and astronomy, in whose lab Cassidy works. "They do this by forming positronium, which is spontaneously emitted from the surface. The free positronium lives more than 200 times longer than the surface positrons, so it is easy to detect."

Study results appear in the July 15 issue of Physical Review Letters.

The researchers chose silicon in their experiments because it has wide application in electronics, is robust, cheap and works efficiently.

"Indeed, at very low temperatures, silicon may be the best thing there is for producing positronium, at least in short bursts," Cassidy said.

The researchers' eventual goal is to perform precision measurements on positronium in order to better understand antimatter and its properties, as well as how it might be isolated for longer periods of time.

Cassidy and Mills were joined in the research by Harry Tom, a professor and the chair of physics and astronomy, and Tomu H. Hisakado, a graduate student in Mills's lab.

In the near future, this research team hopes to cool the positronium down to lower energy emission levels for other experimental uses, and create also a "Bose-Einstein condensate" for positronium – a collection of positronium atoms that are in the same quantum state.

"The creation of a Bose-Einstein condensate of positronium would really push the boundaries of what is possible in terms of real precision measurements," Cassidy said. "Such measurements would shed more light on the properties of antimatter and may help us probe further into why there is asymmetry between matter and antimatter in the universe."

Grants from the National Science Foundation and the US Air Force Research Laboratory funded the study.

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2012 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Graduate Center. The campus has an annual statewide economic impact of more than $1 billion.

A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.ucr.edu

More articles from Physics and Astronomy:

nachricht Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

nachricht Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>