Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Smile, protons, you're on camera

13.11.2007
Radioactivity, discovered more than 100 years ago and studied by physicists ever since, would seem to be a relatively closed subject in science. However, since the 1960s, the pursuit of at least one open question about how nuclei spontaneously eject various particles has continued to nag experimentalists, largely because of an inability to make precise measurements of fleeting, exotic nuclei.

In a paper published this week in Physical Review Letters, an international collaboration of researchers, led by Marek Pfutzner, a physicist from Warsaw University in Poland, takes several steps toward an answer. The scientists describe a first-ever success in peering closely at radioactive decay of a rare iron isotope at the ragged edge of the known nuclear map. The tools used to achieve this result include a novel combination of advanced physics equipment and imaging technology that is found in most off-the-shelf digital cameras.

"We have proved in a direct and clear way that this extremely neutron-deficient nucleus disintegrates by the simultaneous emission of two protons," write the authors.

Pfutzner and his collaborators set out to better understand an exotic form of radioactivity -- two-proton emissions from iron-45, a nucleus with 26 protons and 19 neutrons. The stable form of iron that is most abundant on Earth has 26 protons and 30 neutrons. One possibility was that the iron-45 isotope might occasionally release an energetically linked two-proton pair, known as a diproton. Other possibilities were that the protons, whether emitted in quick succession or simultaneously, were unlinked.

The research was performed at Michigan State University's National Superconducting Cyclotron Laboratory (NSCL), but the key device was a detector built by Pfutzner and his Warsaw University colleagues. Though nicknamed "the cannon" because of its vague resemblance to some sort of space age military device, the detector didn't shoot anything but rather was the target for the beam of rare isotopes produced at the NSCL Coupled Cyclotron Facility.

The detector included a front-end gas chamber that accepted and then slowed rare isotopes traveling at half the speed of light. The back-end imaging system, built around a high-end digital camera with standard charge-coupled device, or CCD, technology, recorded ghostly images of trajectories of emitted protons from the decaying iron-45 nuclei shot into the cannon's mouth.

Analysis of these images ruled out the theorized diproton emission and indicated that the observed correlations between emitted protons were best described by a form of nuclear transformation known as three-body decay. A theory of this process had previously been described by Leonid Grigorenko, a physicist at the Joint Institute for Nuclear Research in Dubna, Russia and a coauthor of the paper.

"There is amazing agreement between the experiment and Grigorenko's theory, which takes into account the complex interplay between emitted pairs of protons and the daughter nucleus," said Robert Grzywacz, a physicist at the University of Tennessee and Oak Ridge National Laboratory and a coauthor of the paper.

Besides shedding light on a novel form of radioactive decay, the technique also could lead to additional discoveries about fleeting, rare isotopes studied at accelerator facilities such as NSCL and Oak Ridge National Laboratory. These isotopes may hold the key to understanding processes inside neutron stars and determining the limits of nuclear existence.

The experiment itself also harkens back to the early days of experimental nuclear physics in which visual information served as the raw data. Before the days of cameras, this information was usually captured by scientists hunched over a microscope counting, for example, tiny flashes as alpha particles struck a zinc sulfide screen under the lens.

"It's perhaps the first time in modern nuclear physics that fundamentally new information about radioactive decay was captured in a picture taken by a digital camera," said Andreas Stolz, NSCL assistant professor and a coauthor on the paper. "Usually, in nuclear physics experiments you have digitized data and several channels of information from electronics equipment, but never images."

Geoff Koch | EurekAlert!
Further information:
http://www.phys.utk.edu/expnuclear/2p_reshigh.html
http://www.msu.edu

More articles from Physics and Astronomy:

nachricht NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center

nachricht Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>