Nov 13, 2020
ESA has adopted Ariel (Atmospheric Remote-sensing Infrared Exoplanet Large-survey), the 4th medium-class space mission of its Cosmic Vision program. Ariel is expected to be launched in 2029 by Ariane 6 from the Guiana Space Centre in Kourou. The French team, composed of CNES, CEA and CNRS, has taken charge of the design, production and delivery of the AIRS spectrometer. Pierre Olivier Lagage, astrophysicist at Irfu, is one of the 2 co-PI for the ARIEL consortium; the other co-PI is Jean-Philippe Beaulieu from IAP.
Oct 02, 2020
Precision measurements via the decay of the Higgs boson into light particles, the photons
The CMS collaboration presented its most achieved measurement of the Higgs boson properties in the two-photon decay channel at the ICHEP conference in August 2020. The results are based on the complete LHC Run 2 data recorded between 2016 and 2018 and show a level of accuracy never achieved before.
Sep 25, 2020
A year and a half after the delivery of the prototype cryomodule (CM00) to ESS, the first production medium beta cryomodule (CM01) has now arrived at the ESS site. It left CEA on September 22, 2020 for a two-day trip to Lund, Sweden. The Irfu teams had previously validated the RF and cryogenic performances of this cryomodule. It will be tested again on the ESS test bench before being integrated in its final position in the accelerator tunnel. This is a first step.
Sep 15, 2020
Thanks to the GANIL accelerated heavy ion collisions and the detection of reaction products with the INDRA detector, it was possible to deduce the evolution parameters of chemical elements in stellar phenomena.    These chemical elements, light nuclei (d, t, 3He, α, 6He…), are created by aggregation of protons and neutrons during the collision between the projectile nucleus and the target nucleus.
Sep 02, 2020
On October 28, 2014, CEA signed a contract with the Israeli research center in Soreq (SNRC) for the construction of a accelerator called SARAF (SOREQ Applied Research Accelerator Facility) by IRFU teams. This agreement is materialized by preliminary and detailed study phases over a period of 18 months (2015 and 2016) opening up to a construction, testing and installation phase on the site that will last 6 years.
Aug 20, 2020
The spectroscopy of a mendelevium isotope, 251Md composed of 101 protons and 150 neutrons, reveals a surprise: when it rotates, it behaves exactly like a lawrencium isotope made of 103 protons and 152 neutrons. The experiment carried out at the University of Jyväskylä in Finland required the most advanced tools to study these rare and ephemeral nuclei: filtering and identification of the nuclei, gamma ray and electron detection.
Aug 07, 2020
In 2019, a first muon tomography had been carried out from several 2D projections, via a collaboration with the University of Florence. The limitations remained numerous, however, because the imaged object was only about twenty centimeters, with very high density contrasts (Lead bricks), and only one fixed telescope operating in the very particular mode of absorption. One by one, all these limitations were removed through a complete redesign of the algorithms and optimization of the computing times.
Aug 03, 2020
Photon-photon elastic scattering is a very rare phenomenon in which two real photons interact producing a new real photon pair. The direct observation of this process at high energy, impossible during decades, was done by ATLAS [1] and CMS [2] experiment at CERN between 2016 and 2019. These successes have led the two collaborations to strengthen their involvement in this new field, leading to a new measurement, currently being published by the ATLAS experiment [3].
Jul 28, 2020
Link between magnetars and Fast radio bursts
An international campaign including ground-based and space telescopes, including the INTEGRAL satellite, discovered end of April 2020 very short pulses in both X-rays and radio waves coming from a compact object in the Galaxy, the magnetar SGR 1935+2154. The simultaneous observation of these signals is seen for the first time in this type of source and attests a connection between magnetars and Fast radio bursts, a class of radio sources whose origin is today poorly known.
Jul 23, 2020
Meteorites are bombarded throughout their journey by cosmic radiation. This cosmic ray exposure (CRE) is a formidable footprint of their history, provided of course that we know how to decipher it. The interaction of cosmic radiation with the atomic nuclei constituting the meteorite will produce so-called cosmogenic isotopes, very often radioactive.
Jul 21, 2020
The combination of the AGATA multi-detector [right] and the VAMOS spectrometer [left] showed that the balance between the two contributions was more complex than previously envisaged.
Jul 20, 2020
The Sloan Digital Sky Survey (SDSS) published in July a complete analysis of the largest three-dimensional map of the Universe ever created, reconstructing the history of its expansion over a period of 11 billion years.
Jul 15, 2020
In order for the images produced by the future MRI to be free of distortions or artifacts, the magnetic field generated by the Iseult magnet must be homogeneous to 0.5 PPM (parts per million) around the patient's brain. To meet this challenging specification, it was necessary to provision means of "shimming" the field, i.e. of correcting all the small defects that would inevitably arise from the manufacturing process.
Jul 11, 2020
That's one wall the White Walkers won't cross. An international collaboration bringing together the IRFU (Université Paris-Saclay), the Astronomy Institute of the University of Hawaii, the LPC (Université Clermont Auvergne), the IP2I (Université Claude Bernard de Lyon), and the Racah Institute of Physics (Hebrew University of Jerusalem), has discovered an immense structure in the distribution of galaxies, called the "South Pole Wall".
Jul 08, 2020
Scientists from the large cosmological survey SDSS/eBOSS have constructed the first so-called "tomographic" map of the far Universe on a very large scale, which until now only existed in one dimension, along the line of sight of the ground-based telescope. To do this, they used the latest Lyman-alpha forest data, which indirectly plot the density of matter in the direction of bright objects, the quasars. The resulting map covers a cube of 3.26 billion light-years from observations of nearly 10,000 quasars.
Jul 02, 2020
The 2020 edition of the Large Hadron Collider Physics Conference (LHCP) took place from 25 to 30 May 2020. Due to the COVID-19 pandemic, the conference, originally planned to be hosted in Paris, was held entirely online.
Jun 28, 2020
In its standard form, double beta decay is a process in which a nucleus decays into a different nucleus and emits two electrons and two antineutrinos (2νββ). This nuclear transition is very rare, but it was detected in several nuclei with sophisticated experiments. If neutrinos are their own antiparticles, it’s possible that the antineutrinos emitted during double beta decay annihilate one another and disappear.
Jun 17, 2020
GANIL hosted the annual IPAC conference in GANIL but not physically in Caen but “virtually” (due the pandemic conditions). This first virtual conference was “attended ” by 3000 people from the world wide accelerator community, representing around 300 institutions/laboratories. The conference consisted of 77 prerecorded talks lasting around 25 hours and two sessions, the awards and the closing ceremony were broadcast live. A summary of statistics can be accessed here.
Jun 08, 2020
After more than four years of research and development, design and manufacturing work, the MFT (Muon Forward Tracker), a new detector that will equip the ALICE experiment at the LHC, has seen its construction finalized and is currently under commissioning at CERN.
Jun 04, 2020
On May 18th 2020, ESO formally closed the preliminary design review of the ELT/METIS thermal infrared instrument. Following this important milestone, the instrument enters into the final design phase (phase C) in which the its design will be frozen just before its building.
Jun 02, 2020
VLT/SPHERE observations of the star AB Aurigae pinpoint a giant planet in formation
Motivated by unusual features recently observed with the ALMA instrument in a proto-planetary disc around the star AB Aurigae, an international team of astrophysicists including a researcher from the Department of Astrophysics / Laboratory AIM of the CEA-Irfu of Paris-Saclay has just obtained a very sharp high-contrast image of a S-shasped sub-structure in the gaseous and dusty disc surrounding the star.
May 29, 2020
The simple question “Where does the Periodic Table end?” has excited scientific interest for a long time. In this context, understanding the structure of the heaviest nuclei, and through it their stability, is of major importance. A decade ago, there was no promising path to tackle this scientific quest.
May 20, 2020
The fourth catalog of Fermi-LAT sources comes on line
The Fermi-LAT collaboration has published its fourth source catalog, named 4FGL. Based on eight years of data, it contains 5064 celestial objects emitting gamma rays at energies around 1 GeV, adding more than 2000 high-energy sources to the previous collection (published in 2015). More than one fourth of the objects are of unknown nature, calling for numerous follow-up studies.
May 13, 2020
The EUPRAXIA project has just completed its design study phase with the delivery of the Conceptual Design Report (CDR) at the end of 2019. The strong involvement of IRFU, particularly in the field of particle beam physics, has made it possible to show that solutions exist for the realization of a plasma wakefield accelerator, with a beam quality approaching that of conventional accelerators.
Apr 29, 2020
Nucleons (protons and neutrons), the components of the atomic nucleus, can be polarized. This means that their spins are preferentially aligned along a quantization axis. The spin is a quantum property of a particle and has its classical analogue in a spinning top. The strong interaction that acts among nucleons in the atomic nucleus is sensitive to the polarization.
Apr 15, 2020
We live in a world of matter – because matter overtook antimatter, though they were both created in equal amounts by the Big Bang when our universe began. As featured on the cover of Nature on 16 April 2020, neutrinos and the associated antimatter particles, antineutrinos, are reported to have a high likelihood of differing behaviour that offers a promising path to explaining the asymmetry between matter and antimatter. These observations may explain this mysterious antimatter disappearance.
Mar 13, 2020
The highest magnetic fileds of the Universe reproduced by numerical simulations
Magnetars are neutron stars endowed with the strongest magnetic fields observed in the Universe, but their origin remains controversial.
Mar 10, 2020
INCL (Liège intranuclear cascade) is a simulation code known for its ability to model light particle-nucleus interactions. It is used in very various fields, such as proton therapy, neutron sources, radioactive ion beams or ADS's (Accelerator Driven Systems). In order to extend its capabilities in the field of higher energy reactions, in connection with cosmic rays or with the study of hypernuclei, a team of physicists led by Irfu has recently developed a new version of the code involving strange particles.
Feb 18, 2020
Following SPIRAL2's commissioning authorization issued by the French Nuclear Safety Authority (ASN) on July 8, 2019, many crucial steps were successfully completed by the end of 2019. A first proton beam was accelerated to 33 MeV, the nominal energy by the SPIRAL2 linear accelerator (LINAC) and a first test experiment was achieved the Neutron For Science (NFS) experimental room. These first results in 2019 are very promising.
Feb 13, 2020
To measure cosmological parameters, the Euclid space telescope will use two main probes: gravitational lensing (Weak Gravitational Lensing) and galaxy distribution (Galaxy Clustering). These measurements will allow us to study dark energy and dark matter, which affect the growth of cosmic structures and the accelerated expansion of the Universe.


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