Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Measurements at CERN help to re-evaluate the element of life

14.01.2005


Results from experiments at CERN and the Jyväskylä Accelerator Laboratory in Finland, reported in Nature today, cast new light on the primary reaction that creates carbon in stars. All the carbon in the Universe, including that needed for carbon-based life forms such as ourselves, has been made in the hearts of stars through what is known as the “triple alpha reaction”. The new findings modify the rate at which the reaction occurs and have broad implications for astrophysics, from the formation of the first stars to the creation of the heaviest elements in supernovae.



"The connection between the subatomic world and the cosmos is fascinating. The example of carbon is an old problem with contributions from many heroes in the field. It is a pleasure to be able to answer some of the questions they have left for us. It is the technological development in the intervening years, for example at ISOLDE, that has made this possible," says from Hans Fynbo of the University of Aarhus, lead author of the paper.

The big bang created mainly only hydrogen (mass 1) and helium (mass 4), because there are no long lived atomic nuclei with mass 5 and 8 to make the bridge to heavier elements such as carbon (mass 12). But in the hearts of stars the formation of carbon is possible through the triple-alpha reaction, where three helium nuclei (alpha particles) fuse to make to make a nucleus of carbon-12.


Rather than recreate the scorching conditions inside stars, the team from CERN and eight other European universities and institutes watched the reaction unfold in reverse, as nuclei of carbon-12 broke into three alpha particles. To do this, they created boron-12 and nitrogen-12, which are short-lived isotopes of the elements that flank carbon in the Periodic Table. The boron-12 was produced at CERN’s ISOLDE facility, while the nitrogen-12 was created at the IGISOL facility at the Jyväskylä Accelerator Laboratory at the University of Jyväskylä. These unstable nuclei soon transformed into carbon-12, through beta decay, in which a proton changes into a neutron or vice versa; the carbon-12 then broke into three alpha particles.

The ISOL method – isotope separation on line - originally pioneered and developed mainly at CERN played an important role in these experiments. “While ISOLDE at CERN could make the boron-12, IGISOL in Jyväskylä was needed to produce the nitrogen-12. This facility in Finland was specifically developed to complement ISOLDE’s performance through its ability to produce very short-lived radioisotopes of chemically reactive elements such as nitrogen," said Juha Äysto, head of the group responsible for the experiment at the University of Jyväskylä.

By measuring precisely the timing and energies of alpha particles shooting from the samples, the researchers were able to infer the energy states of the carbon nuclei just before decay. With this information in hand, they were able to determine the rate for the triple alpha process over a wide range of temperatures, from 0.01 – 10 billion K.

For the conditions in most stars, the researchers’ calculated rates for the triple alpha process agree with previous calculations. But their findings suggest the triple alpha rate at the relatively low temperatures of the Universe’s first stars (around 0.05 billion K), which began without carbon, was much faster. This in turn implies that the amount of carbon that could catalyze hydrogen burning in the first stars was produced twice as fast as previously thought.

At high temperatures, above 1 billion K, the new results indicate that the triple alpha process would work significantly slower than previous estimates, modifying the process of element production - nucleosynthesis – in supernovae. These explosions of old massive stars are a major source of the heaviest elements, those more massive than iron, through interactions in the surrounding shock wave. The new results suggest a reduction in the amount of nickel-56 produced with subsequent effects for heavier elements.

This work was carried by a team from CERN and eight other European universities and institutes.

James Gillies | alfa
Further information:
http://www.cern.ch

More articles from Physics and Astronomy:

nachricht Temperature-controlled fiber-optic light source with liquid core
20.06.2018 | Leibniz-Institut für Photonische Technologien e. V.

nachricht New material for splitting water
19.06.2018 | American Institute of Physics

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Creating a new composite fuel for new-generation fast reactors

20.06.2018 | Materials Sciences

Game-changing finding pushes 3D-printing to the molecular limit

20.06.2018 | Materials Sciences

Could this material enable autonomous vehicles to come to market sooner?

20.06.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>