Postdoctoral PSICHÉ beamline

Located on the Paris-Saclay plateau, about 20 kilometers from the capital, the SOLEIL synchrotron is one of France's leading research facilities. Since it began operating in 2008, it has served the national and international scientific communities. Research conducted at SOLEIL covers a wide range of scientific and industrial fields — including physics, biology, chemistry, materials science, environmental science, Earth sciences, and cultural and natural heritage — all connected to current societal challenges. Experiments carried out on the beamlines rely on the use of synchrotron light emitted by electrons accelerated to nearly the speed of light within a storage ring. SOLEIL is jointly supervised by the CNRS and the CEA and offers its staff a dynamic, innovative, multidisciplinary, and international working environment.

At the forefront of technology, SOLEIL II is an ambitious project designed to provide new opportunities for scientific and industrial research. SOLEIL II consists of a major upgrade of the existing infrastructure and aims to significantly improve the performance of electron accelerators and beamlines. It is designed to address major current and future societal challenges, particularly in areas such as advanced materials research, energy and sustainable development, health and well-being, and the environment.

Construction work on the SOLEIL II project began in 2024, marking the start of a phase of development and technological innovation. In parallel, the existing facility will remain operational until the fall of 2028. SOLEIL II is scheduled to start operations in 2030, with a gradual ramp-up phase continuing until 2035.

Context and Missions

Synchrotron SOLEIL seeks to hire a postdoc in materials science. This position is opened for the PSICHÉ beamline. The contract will last 24 months.

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: 15-120 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), 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 PSICHE beamline is a high-end facility that attracts users worldwide.

The PSICHÉ team is currently made up of three scientists including the beamline manager, one technician, two post-docs, one PhD student and one emeritus.

The postdoc will work on the PSICHÉ beamline under the joint supervision of Nicolas Guignot (beamline manager) and Agnès Dewaele (CEA, Commissariat à l’Energie Atomique).

She.He will be involved in the scientific, technical, and methodological aspects of the beamline team activities and will actively participate in the user support called local contact. That means preparing the beamline for the experiments, helping the users with the management of the presses, data acquisition and data treatment if necessary. This activity typically represents 3 weeks of beamtime (including week-ends) every 6 months. Working closely with renowned international researchers for limited periods of time is an important asset of the position, achieving visibility while still allowing the postdoc to conduct her.his own research program.

For this program she.he will be granted in-house research beam time and will have to submit proposals to the peer review committees.

She.He will publish her.his results and present them at national and international conferences.

Responsibility and tasks:

The postdoc research program will be divided into two tasks:

• Implementation and exploitation of acoustic emissions measurements under extreme conditions

PSICHE is equipped with a high-end large volume press experimental station designed to precisely measure various physical properties of materials, in particular liquids, at extreme conditions. Available techniques are: high-speed radiography, tomography, including high-speed (morphology, volume), xray diffraction (structure), Beer-Lambert absorption (density) and the recently added sound velocity measurements (elasticity). The beamline now seeks to implement acoustic emissions measurements, with applications in materials sciences, solid-state physics and Earth sciences. The postdoc will lead the development and integration of the technique in association with external partners and the PSICHE staff and develop a research program adapted to the new equipment. Possible topics include phase transitions studies, tracking faults and fractures in rocks or advanced materials at extreme conditions in combination with high-speed tomography, etc.

• Exploitation of new pyrometry diagnostics + X-ray diffraction in laser heated diamond anvil cells

The PSICHÉ beamline has recently developed an innovative setup allowing for real-time measurement of sample surface temperature maps in laser heated diamond anvil cells. By combining this new technique with X-ray diffraction and thermo-mechanical modeling, and in association with external partners (CEA) and the PSICHE staff, the postdoc will be able to develop a research program adapted to her/his scientific interest, e.g. the study of crystallization kinetics, melting, thermal properties of materials under extreme conditions, etc.

In addition to these tasks, the candidate can propose other research programs.

Profile

The candidate should have a PhD degree in physics / chemistry / materials science or Earth sciences. 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 condensed matter physics basics.

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

We are looking for someone showing curiosity, dynamic, autonomous, and liking working in a team.

Working Conditions

This is a 2-years position.

The postdoc will have to occasionally go and work at the CEA DAM (Bruyères-le-Châtel).

Assistance to users imposes some on-call duty periods and may require, in case of need, on-site interventions outside regular working hours.

Benefits :

• 26 days of paid vacation + up to 2 additional split days + 23 RTT (reduction of working time) days per full year of work, based on a 40-hour work week.
• Mandatory health insurance (basic plan) costs €19.35 per month for the employee (with an employer contribution of €174.15, corresponding to 90% of the premium), covering household members (spouse/partner + children).
• We also offer an optional supplementary health plan for €26.69 per month covering your household (spouse/partner + children).
• Access to a provident scheme that supplements the benefits of the mandatory French Social Security system, which are often insufficient. It compensates for loss of income in case of inability to work, ensuring the standard of living of the insured and their family in difficult circumstances: death, incapacity for work, or disability resulting from illness or accident.
• Possibility to open a Time Savings Account (CET) after one year of seniority.
• On-site corporate catering at SOLEIL, with subsidized meals.
• Family-related benefits depending on individual situations: family allowance supplement, additional days off under certain circumstances, marriage and birth bonuses, etc.
• Social and cultural activities offered by SOLEIL’s Social and Economic Committee (CSE).