Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mainz laser system allows determination of atomic binding energy of the rarest element on earth

05.07.2013
Ionization potential of radioactive element astatine measured

The radioactive element astatine, the name of which is derived from the Greek word for 'instability,' is so rare on earth that it has not yet been investigated to any greater extent and, as a consequence, very little is known about it.


Close-up of the Mainz laser system
photo: Pascal Naubereit


View of the Mainz laser system
photo: Pascal Naubereit

Using artificially generated astatine, the Mainz-based physicist Sebastian Rothe has now managed for the first time to experimentally explore one of its fundamental parameters, the ionization potential, and thus determine one of the most important properties of the rare element.

The ionization potential is the binding energy, i.e., the amount of energy required to remove an electron from an atom's outer shell. It determines the entire chemical binding characteristics of that element. The measurements were undertaken at the laboratory of the CERN European Organization for Nuclear Research near Geneva using special lasers developed by the LARISSA working group at the Institute of Physics at Johannes Gutenberg University Mainz (JGU). The online journal Nature Communications recently published the findings.

Astatine is the rarest naturally occurring element on earth. The earth's mantel is estimated to contain only 0.07 grams. Together with fluorine, chlorine, and iodine, it is a member of the halogen group, and is formed as a result of the natural decay of uranium. Nuclear physicists now know of more than 20 isotopes which are all extremely short-lived and decay with a half-life of no more than eight hours. Alpha rays are emitted during decay, making the element particularly interesting for targeted cancer therapy thanks to its short lifespan. "Astatine is the only halogen we have known absolutely nothing about to date", explained Professor Klaus Wendt, head of the LARISSA working group at the Institute of Physics at Johannes Gutenberg University Mainz (JGU).

A doctoral candidate and member of this work group, Sebastian Rothe, investigated the ionization potential of astatine using laser spectroscopy and determined it had a value of 9.31751 electron volts (eV). The measurements were conducted at CERN in Geneva and were extrapolated and confirmed at the Canadian research center for particle and nuclear physics TRIUMF in Vancouver in Canada.

LARISSA is an acronym for 'Laser Resonance Ionization for Spectroscopy in Selective Applications'. The technique is based on work originally conducted by Mainz physicist Professor Ernst Otten more than 30 years ago using the isotope mass separator ISOLDE at CERN. It is now the technique of choice employed at almost all large-scale research facilities throughout the world to produce and examine exotic radioisotopes and is commonly used applying the Mainz laser system. It involves the use of laser light for the gradual optical excitation of a valence electron of a selected atomic species until the point of ionization.

"Astatine is the last naturally occurring element whose ionization potential had yet to be determined experimentally," stated Rothe. The binding energy of the electrons in its outermost shell determines what chemical reactions astatine will undergo and thus the stability of its chemical bonds. It is believed that the astatine isotope 211 may have a major pharmaceutical potential. It is an exceptional candidate for use in cancer therapy because of its decay profile, the aggressiveness of its alpha radiation, and the limited range of its radiation. It is also a member of the halogen family, which can be readily introduced into the human body to be attached directly to cancer cells.

Publication
Sebastian Rothe et al.
Measurement of the first ionization potential of astatine by laser ionization spectroscopy
Nature Communications, May 2013
DOI: 10.1038/ncomms2819
http://www.nature.com/ncomms/journal/v4/n5/full/ncomms2819.html
Images
http://www.uni-mainz.de/bilder_presse/08_physik_quantum_astat_01.jpg
Close-up of the Mainz laser system
photo: Pascal Naubereit
http://www.uni-mainz.de/bilder_presse/08_physik_quantum_astat_02.jpg
View of the Mainz laser system
photo: Pascal Naubereit
Contact and further information
Professor Dr. Klaus Wendt
Larissa work group
Institute of Physics
Johannes Gutenberg University Mainz (JGU)
D 55099 Mainz, GERMANY
phone +49 6131 39-22882
fax +49 6131 39-23428
e-mail: klaus.wendt@uni-mainz.de
http://www.larissa.physik.uni-mainz.de/index_ENG.php

Petra Giegerich | idw
Further information:
http://www.uni-mainz.de
http://www.nature.com/ncomms/journal/v4/n5/full/ncomms2819.html

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

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 “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

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,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>