Post-doctoral position in magnetism

SOLEIL is the French national synchrotron facility, located on the Saclay Plateau near Paris. It is a multi-disciplinary instrument and research laboratory whose mission is to conduct research using synchrotron radiation, to develop cutting edge instrumentation on the beamlines, and to make these developments available to the scientific community. SOLEIL synchrotron, a unique tool for both academic research and industrial applications across a wide range of disciplines including physics, biology, chemistry etc., opened in 2008. It is used annually by thousands of researchers from France and abroad. SOLEIL is based on a synchrotron source that is state-of-the-art both in terms of brilliance and stability. This large scale facility, a partner of the Université Paris Saclay, is a “publicly owned” private company, founded by the CNRS and the CEA.

To remain competitive in an effervescent international context (in which several synchrotron radiation sources currently in operation are engaged in major improvement programs, known as "upgrades"), and in order to develop scientific and technological solutions to meet to the major challenges of society (particularly in the fields of advanced materials, life and health sciences, environment, or even sustainable energy), SOLEIL [www.synchrotron-soleil.fr] studies a major upgrade of its accelerators and beamlines. The project is now in a Technical Design Report phase (TDR) which will be followed by a construction phase.

This position is open in the Magnets and Insertion Devices group in the Accelerators and Engineering Division.

The post-doctoral student in magnetism, or the fixed-term contract, will work in the Magnet and Insertions group made up of a group leader and her deputy, supervising four engineers and four technicians. The group is responsible for the accelerator magnets (linac, booster, beamlines, storage ring) and magnetic insertion devices (undulators or wigglers). This activity is divided between projects for the construction of magnetic devices (electromagnetic or permanent magnet) and the maintenance of equipment in operation on the accelerators. The group is highly involved in the preparation of SOLEIL II with, in particular, the development of undulators creating a permanent periodic magnetic field making possible to produce very intense and collimated synchrotron radiation. Undulators are key components of new generation light sources, and in this context, SOLEIL has obtained, jointly with other synchrotron radiation or free electron laser facilities, a European LEAPS-INNOV contract, of which SOLEIL coordinates WP6 on innovative undulators and leads the task for the development of a 12 mm period cryogenic undulator prototype.

 I.Mission

The post-doctoral student /CDD will carry out the construction of the 1m long cryogenic undulator prototype of 12 mm period. The magnetic assembly has a series of alternating PrFeB permanent magnets with poles to channel the field lines. Working at cryogenic temperature achieves a stronger magnetic field and an increased resistance to demagnetization. For the same spectral range to be covered, shorter periods can be selected, leading to an increase in the number of periods and therefore in the radiated flux. For this work, he/she will be led by an expert engineer in cryogenic undulators and partially assisted by a technician.

II. Responsibility and Tasks

Its activity will include several aspects:

1.       Modeling

The post-doctoral student /CDD will perform the magnetic modeling of the CPMU12 undulator using the RADIA code in Python, including sizing and a sensitivity study. He/she will be able to perform a benchmarking with OPERA. He/she will also model the production of the expected radiation under SRW.

2.      Validation of the test bench by magnetic measurements at room temperature

A first "supermodule" test bench containing 8 undulator periods to validate the behavior of the magnets and poles and their adjustment in the mechanical support, has been assembled, and mechanically and magnetically characterized. An improved version with a modification of the holding of the poles is under study. The post-doctoral student /CDD will carry out the experimental characterization of the new version test bench of super-modules with mechanical verifications and magnetic measurements with the Hall effect probe and the rotating coil. He/she will complete the characterization with a stretched wire and he/she will compare to coil measurements. He/she will compare the measurements to the model prediction.

3.      Construction and characterization of the prototype at room temperature

Once the supermodule has been validated, he/she will undertake the construction of the 1m long prototype. He/she will rely on the measurement of robot-assisted supermodules, under development at SOLEIL. He/she will characterize the assembled prototype using magnetic measurements and make the necessary corrections.

4.      Characterization of the prototype at cryogenic temperature.

Once the supermodule has been validated, he/she will participate in the assembly of the vacuum chamber and the components of the assembled magnetic measurement bench. Then, he/she will magnetically characterize the undulator at cryogenic temperature (77 K) and will carry out the corrections to be made following the deformation of the various parts resulting from the change in temperature. He/she will then calculate the radiation produced from the measured magnetic field and compare it to the model system.

5.      Dissemination

The post-doctoral student / CDD will be required to present the results in scientific meetings. He/she will contribute to the dissemination of results through scientific publications.

 III.Education and Experience

This position concerns a candidate with an engineering degree or a doctorate, with knowledge in the fields of magnetism and/or electromagnetic radiation

IV. Conditions générales

The post-doctoral student / fixed-term contract may be required to travel to conferences, LEAPS-INNOV meetings or participate in visits by associated teams.