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!
NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center
Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses