Featured Research

from universities, journals, and other organizations

Physicists discover new way to produce antimatter-containing atom

Date:
July 11, 2011
Source:
University of California - Riverside
Summary:
Physicists 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. The method works at almost any temperature -- including very low temperatures.

Researchers Tomu H. Hisakado, Harry Tom, Allen Mills and David Cassidy have found a new way to produce positronium.
Credit: M. Kelley, UCR Strategic Communications

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.


Story Source:

The above story is based on materials provided by University of California - Riverside. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. B. Cassidy, T. H. Hisakado, H. W. K. Tom, and A. P. Mills Jr. Photoemission of positronium from Si. Physical Review Letters, 2011; (in press)

Cite This Page:

University of California - Riverside. "Physicists discover new way to produce antimatter-containing atom." ScienceDaily. ScienceDaily, 11 July 2011. <www.sciencedaily.com/releases/2011/07/110711172229.htm>.
University of California - Riverside. (2011, July 11). Physicists discover new way to produce antimatter-containing atom. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2011/07/110711172229.htm
University of California - Riverside. "Physicists discover new way to produce antimatter-containing atom." ScienceDaily. www.sciencedaily.com/releases/2011/07/110711172229.htm (accessed August 20, 2014).

Share This




More Matter & Energy News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

AFP (Aug. 19, 2014) A solar cell that resembles a flower is offering a new take on green energy in Japan, where one scientist is searching for renewables that look good. Duration: 01:29 Video provided by AFP
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins