LEARN - Study and Applications of Nuclear Reactions

Jul 30, 2023

Jan 23, 2023

The origin of the reactor antineutrino anomalies revealed?

Reactor antineutrino anomalies are a decade-long puzzle in neutrino physics. They are manifested by deviations of the order of a few percent between measurements and predictions. These deviations have been observed in the number of antineutrinos measured by more than a dozen experiments at nuclear reactors, and in the shape of the kinetic energy distributions by the seven most recent ones.

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The origin of the reactor antineutrino anomalies revealed?

Jan 12, 2023

The Stereo adventure has not been sterile

The final results of the Stereo experiment have just been published in the journal Nature. A record of precision is established for the spectrum of neutrinos emitted by the fission of 235U, measured between 9 and 11m distance from the ILL reactor core in Grenoble. The hypothesis of a sterile neutrino to explain the reactor neutrino anomaly is rejected. The quality of these direct neutrino measurements now surpasses that of the underlying nuclear data describing the beta decays of fission products.

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Jun 17, 2022

Study of neutron capture gammas from uranium isotopes

The DPhN, in collaboration with the Department of Reactor Studies of Cadarache (DES) and the Institute of Particle and Nuclear Physics of Charles University in Prague (Czech Republic), studied the properties of gamma rays emitted by uranium isotopes during neutron capture reactions. Gamma-ray spectra measured at CERN's n_TOF facility were used as a test bed for nuclear reaction models and their ingredients, including the photon strength function that characterises the ability of a nucleus to emit or absorb photons.

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Study of neutron capture gammas from uranium isotopes

Jul 23, 2020

INCL, a key to deciphering the history of meteorites

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.

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Mar 10, 2020

The strange version of INCL

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.

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Oct 30, 2019

FIFRELIN and STEREO at the Crossroads of Cultures

The FIFRELIN code simulates nuclear fission and de-excitation of the nuclei produced therein. STEREO is a compact neutrino detector that looks for a hypothetical sterile neutrino. Two a priori separate topics developed at CEA, the first at DEN, the second at DRF/Irfu, which have however recently met to achieve unprecedented precision on a crucial ingredient in the detection of neutrinos: the de-excitation of a gadolinium nucleus after the capture of a neutron.

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Mar 21, 2019

STEREO is moving up a gear

The STEREO experiment releases new results based on the detection of about 65000 neutrinos at short distance from the research reactor of the ILL-Grenoble. The improved accuracy is rejecting the hypothesis of a 4th neutrino in a large fraction of the domain predicted from the reactor neutrino anomaly. Profiting from a good control of the detector response, STEREO now also releases its first absolute measurements of the neutrino rate and the spectrum shape.

Jul 27, 2018

First laps of the NFS converter at Spiral2

NFS (Neutrons For Science) is an experimental area of the Spiral2 facility (Ganil, France) that will provide high intensity neutron beams for energies ranging from 0.5 to 40 MeV. The neutrons will be created by collision of Spiral2 charged particles with carbon, beryllium or lithium targets, thanks to a key element of NFS, the converter. The design of this one is a real challenge because it has to withstand a high power deposited by Spiral2's intense beams.

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Mar 27, 2018

STEREO constrains the existence of a 4th neutrino

The STEREO experiment presented its first physics results at the 53rd Rencontres de Moriond1. STEREO is a neutrino detector made up of six scintillation liquid cells that has been measuring, since November 2016, the electronic antineutrinos produced by the Grenoble high neutron flux reactor 10 metres from the reactor core. The existence of a fourth neutrino state, called sterile neutrino, could explain the deficit in neutrino flux detected at a short distance from nuclear reactors compared to the expected value.

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STEREO constrains the existence of a 4th neutrino

Jan 30, 2013

Simulating spallation reactions around the world

For many years, the SPhN Spallation group has been developing, in close collaboration with the University of Liège, a model describing spallation reactions, called INCL. Based on its remarkable performance in an international evaluation, this model has just been included in three of the major simulation codes used worldwide to model and design the facilities in which these reactions occur.

Division of Electronics, Detectors and Computing for Physics (DEDIP)

Institute of Research into the Fundamental Laws of the Universe