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Development of a moderator for the production of cold neutrons H/F

Vacancy details

General information


The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.

Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.

The CEA is established in ten centers spread throughout France



Division description

The Basic Research Division conducts research at the highest international level in the fields of physics, chemistry, biology, and climate and environmental sciences, in direct relation to CEA's missions for Energy.

Description de l'unité

The missions of the Léon Brillouin Laboratory (LLB) are the development of its own research using neutron scattering, the construction, maintenance and operation of instruments (outstations) around different neutron sources in Europe, as well as training in neutron scattering techniques. The LLB is also working, with the French neutron community, on a project of compact neutron source using a gas pedal.
In this context, building, imagining and exploiting neutron beams to perform physics experiments is still a formidable challenge for the IRAMIS/LLB teams. These experiments are essential to "invent" the neutron diffraction of tomorrow

Position description


Condensed Matter Physics, chemistry, nanosciences


Fixed-term contract

Job title

Development of a moderator for the production of cold neutrons H/F

Socio-professional category


Contract duration (months)


Job description

Post-doc / Neutronics.

Development of a moderator for the production of cold neutrons at the IPHI – Neutrons facility at the CEA Saclay.



The landscape of French and European neutron scattering is changing. Several older research reactors have already shut down and further closures are scheduled for the current decade. To overcome these closures, the construction of a new type of neutron source using low-energy, high-current accelerators (HiCANS) is proposed by various institutes across Europe. Among the projects, we can mention SONATE in France [1], HBS in Germany [2] or ARGITU in Spain.


We aim at developing a moderator for the production of “cold” neutrons. A cryogenic loop for hydrogen liquefaction was recently built at the Laboratoire Léon Brillouin (LLB). With the support of other CEA departments (DES/SERMA and DRF/DPhN), Monte-Carlo modelling of neutron transport in the moderator will be carried out to understand the parameters allowing optimization of the geometry of the moderator (coupling with the neutron production target, pre-moderator, reflector). The existing loop will then be optimized to be integrated into the IPHI – Neutrons source at Saclay [3]. The neutronics performances will be evaluated and compared with the models. The equipment will ultimately be used to perform neutron scattering experiments. Collaborations with the partners of the ELENA network are envisaged [4]. This platform will make it possible to test new materials and geometries for next-generation cold neutron moderators.


[1] SONATE, an accelerator-driven neutron source

[2] HBS, High Brilliance Neutron Source

[3] IPHI – Neutrons project

[4] ELENA, European Low Energy accelerator-based Neutron facilities Association

Applicant Profile


1.      Knowledge in phyics

2.      Instrumentation

3.      Monte-Carlo simulation (desirable, ex. GEANT4)

4.      Cryogenics (desirable)


Keywords : neutronics, Monte-Carlo, instrumentation, cryogenics.


The offer refers to a fixed term contract of 24 months at the CEA Saclay.
The level of skill required is that of a beginner engineer – physicist.

The deadline for submitting applications is November 7th, 2022.


Contact : Frédéric OTT, Laboratoire Léon Brillouin, CEA Saclay,

Position location



Job location

France, Ile-de-France, Essonne (91)




Position start date