Post-doctoral position: PSICHE beamline - Study of the physical properties of materials by exploiting new experimental techniques in the field of high pressure science

SOLEIL is the French national synchrotron facility, located on the Saclay Plateau near Paris. It is a multi-disciplinary instrument and a research laboratory, whose mission is to run research programs using synchrotron radiation, to develop state-of-the-art instrumentation on the beamlines, and to make those available to the scientific community. SOLEIL, a unique tool for both academic research and industrial applications across a wide range of disciplines including physics, biology, chemistry etc., is used by over 5 000 researchers coming from France and abroad. The facility is a “public” company employing about 500 people, founded by the CNRS and the CEA, and partner of the Paris-Saclay University.

Synchrotron SOLEIL seeks to hire a postdoc in materials science in collaboration with the CEA. This position is opened for the PSICHÉ beamline. It will start in April 2023 at the latest and will last 12 months, renewable once.

The PSICHÉ (Pressure Structure and Imaging by Contrast at High Energy) beamline is dedicated to X-ray diffraction under extreme conditions (pressure-temperature) and to tomography at high energy, from ambient to extreme conditions. The source is an in-vacuum wiggler that is used to produce a wide variety of beam modes, from a large parallel white/pink beam to a microfocused monochromatic beam. We have two hutches, one dedicated to white/pink beam (energy range: 15-100+ keV) and another to monochromatic beam (20-50 keV). Extreme pressure and temperature conditions can be generated using different equipment: a 1200-ton multi-anvil press, Paris-Edinburgh presses (including tomography at extreme conditions), and diamond anvil cells (including a double-sided laser heating facility). The use of multiple techniques, and the combination of complementary techniques, are important features of the beamline.

The scope of the scientific cases is very large: from biology and paleontology to materials science, high-pressure physics and geophysics.

The PSICHÉ team is currently made up of a total of three permanent staff, two scientists and one technician, plus one post-doc.

I. Mission

The postdoc will work on the PSICHÉ beamline under the joint supervision of Nicolas Guignot (beamline manager) and Agnès Dewaele (CEA DAM).

She/He will actively participate to the user-support program (X-ray diffraction using a multi-anvil press and diamond anvil cells) and will be involved in the scientific, technical, and methodological activities of the beamline. That means preparing the beamline for the experiments, helping the users with the management of the presses, data acquisition and data treatment if necessary.

She/He will develop a research program (see next section). She/He will be granted in-house research beam time and while also submitting proposals to the peer review committees. She/He will publish her/his results and present them at national and international conferences.

II. Responsibility and Tasks

The postdoc will work on two topics:

• New pyrometry diagnostics + X-ray diffraction in laser heated diamond anvil cells

The PSICHÉ beamline has an innovative setup allowing for real-time measurement of surface temperature maps of the laser-heated samples. By combining this new technique to new laser heating methods and x-ray diffraction it is possible to develop new research fields, such as the study of the crystallization kinetics of materials at extreme conditions.

• Sound velocity measurements in multi-anvil presses

The “large volume presses” experimental station of the PSICHÉ beamline is multi-technical and designed to precisely measure various physical properties of materials, in particular liquids, at extreme conditions: high-speed radiography (viscosity), tomography, including high-speed (microstructure, density), x-ray diffraction (structure, density), Beer-Lambert absorption (density). The beamline will soon be equipped with a new sound velocity measurement setup that will allow for the measurement of elastic properties of materials as well as the partial melting rate of samples heated to high temperatures. This is part of an ANR project in partnership with LMV (Clermont-Ferrand) and UMET (Lille).

In addition, the postdoc will be involved in the ongoing collaboration between the CEA et the PSICHÉ beamline focused on the development of imaging techniques designed for the study of phase transformations of materials under extreme conditions: P-T conditions, kinetics, microstructures produced.

The studied materials will be technologically interesting metals as well as oxides (simples or relevant for Deep Earth studies).

III. Education and Experience

The candidate should have a PhD degree in physics / chemistry / materials science or Earth sciences, and post-doctoral experience. She/He should have a good knowledge and skills in the field of high-pressure experimentation using large volume presses and/or diamond anvil cells, in a laboratory setup or if possible in a synchrotron radiation facility, as well as a good knowledge of the basics of condensed matter physics.

The postdoc will join an enthusiastic and growing pluri-disciplinary team, benefiting from multiple national and international partnerships.

We’re looking for someone curious, dynamic, autonomous, and who enjoys working in a team.

IV. General conditions

This is a 1-year position, renewable 1 year.

The position is localized to the SOLEIL synchrotron site (Paris-Saclay campus, Saint-Aubin, www.synchrotron-soleil.fr). The postdoc will have to occasionally go and work at the CEA DAM (Bruyères-le-Châtel).

The assistance to users imposes some on-call duty periods (typically 6 days per month in average, including one weekend) and may require, in case of need, on-site interventions outside regular working hours.