Oct 06, 2017

The Cherenkov Telescope Array (CTA) consortium brings together 1300 scientists from 32 countries. They have published their scientific aims in a document over 200 pages long. This is the result of several years of work, and includes contributions from approximately fifteen Irfu researchers involved in X-ray and gamma-ray observatories (Fermi, Integral, XMM-Newton, H.E.S.S., etc.).

Dec 06, 2017

For more than 10 years now, Irfu physicists and engineers have been developing in Saclay the necessary equipment for the GBAR experiment, designed to test the behaviour of antimatter under terrestrial gravity. An important step has just been taken with the installation at the Cern of a new positron source using on an electron linac, and the transport to the Cern of the positron trapping system built at Saclay.

The new source produced its first positrons on November 17, 2017. The installation of the traps is in progress, to be operational when the antiprotons arrive, scheduled for spring 2018.

Jul 13, 2017
The secret of the star magnetic cycles

Thanks to new numerical simulations, a scientific team led by researchers from the Astrophysics Department-Laboratory AIM of CEA-Irfu has succeeded in explaining why the magnetic field of the Sun reverses every 11 years. Scientists have highlighted the existence of a strong feedback between the star magnetic field and its internal rotation profile, with temporal modulations that ultimately determine the period of the cycle. This major discovery in the understanding of the origin of the star magnetic fields is published on July 14, 2017 in the journal Science.

See the video :   The magnetic cycle of the Sun in virtual reality (CEA Astrophysics)

Apr 25, 2017

According to the ALICE collaboration at LHC (CERN), certain rare proton collisions have properties that are similar to those of a quark–gluon plasma. In the past, these properties had been observed for collisions of heavy nuclei only. The physicists are now confronted with a new enigma: how can a state of quark–gluon plasma emerge in a system as "small" as that generated by a collision between two protons?

Jun 14, 2017
An international team has performed the first spectroscopy of the very neutron-rich isotopes 98,100 Kr. The collaboration, led by scientists from the CEA Irfu and RIKEN (Japan)  included several European groups and physicists from IPN-Orsay. This experiment showed that there are two coexisting quantum configurations at low excitation energy in the 98Kr nucleus. The competition between these two configurations, represented by different shapes, has been previously evidenced in the isotopic chains Rb, Sr and Zr  by an abrupt transition from one shape to another, starting from the 60th neutron. This experiment observes however that in the Kr isotopic chain there is a much more gradual transition between these two configurations as a function of neutron number. This study marks a decisive step towards an understanding of the limits of this quantum phase transition regionIt was published in Physical Review Letters [PRL 118, 242501 (2017)].

Oct 31, 2017

The ScanPyramids collaboration has discovered a new void in the heart of the Kheops pyramid. This large vacuum was detected by muonic imaging techniques conducted by three separate teams from Nagoya University (Japan), CEC (Japan) and CEA/IRFU. It is the first discovery of a major internal structure of Kheops since the Middle Ages.

Similar in size to the Great Gallery, an architectural structure located in the heart of the Great Pyramid (47m long, 8m high), this new cavity, called ScanPyramids Big Void, has a minimum length of 30 metres. First observed with nuclear emulsion films installed in the Queen's Chamber (Nagoya University), then detected with a scintillator telescope installed in the same chamber (KEK), it was confirmed with gas detectors, MICROMEGAS, located outside the pyramid (CEA), and thus with a very different angle of view allowing to refine the location of this void. This is the first time that an instrument has detected a cavity located at the bottom of a pyramid from the outside.

These results were published by the ScanPyramids team on November 2, 2017 in the journal Nature.

 

Retour en haut