Job description

Détail de l'offre

Informations générales

Entité de rattachement

Le Commissariat à l'énergie atomique et aux énergies alternatives (CEA) est un organisme public de recherche.

Acteur majeur de la recherche, du développement et de l'innovation, le CEA intervient dans le cadre de ses quatre missions :
. la défense et la sécurité
. l'énergie nucléaire (fission et fusion)
. la recherche technologique pour l'industrie
. la recherche fondamentale (sciences de la matière et sciences de la vie).

Avec ses 16000 salariés -techniciens, ingénieurs, chercheurs, et personnel en soutien à la recherche- le CEA participe à de nombreux projets de collaboration aux côtés de ses partenaires académiques et industriels.

Référence

2020-13508

Description de la Direction

NeuroSpin is an international research center in cerebral imagery located on the campus of Paris-Saclay University. It depends on the JOLIOT Institute.
The objective of NeuroSpin is to push the limits of current brain imaging by ultra-high field MRI / MRS (UHF), and MEG / EEG imaging in order to elucidate the structure and functioning of the healthy brain and sick, of all ages. NeuroSpin is directed by Stanislas Dehaene, Member of the Academy of Sciences.

Description de l'unité

On one hand, methodologists from the BAOBAB unit develop hardware and software technologies to make the most of the prototype equipment and provide the tools for individual & cohort image processing. On the other hand, end users from the UNICOG and UNIACT units exploit the high field scanners towards neuroscience applications: cognition, normal and pathological brain development, psychiatry, the early detection and follow-up of neuro-degenerative diseases… NeuroSpin is thus a rich mix of engineers, physicists, mathematicians, data scientists, psychologists and medical doctors with a fair amount of international representatives. Between 150 and 200 people work there under Stanislas Dehaene's leadership.
Inside the BAOBAB unit, the METRIC lab, led by Alexandre Vignaud, is in charge of bringing the best-quality images from the UHF clinical scanners, in acquisition times made as short as possible. A small team there, led by Alexis Amadon, conducts R&D in MRI instrumentation to address both B0 and B1 field inhomogeneities that arise at UHF. Thus, parallel-transmit RF coils as well as a brain-dedicated B0-shim insert are under development for both 7T and 11.7T scanners... Recently, the METRIC lab obtained a participation in a new European project called M-One.

Description du poste

Domaine

Recherche biomédicale, clinique, préclinique

Contrat

CDD

Intitulé de l'offre

Engineer/scientist position in RF electronics for MRI at Ultra-High-Field H/F

Statut du poste

Cadre

Durée du contrat (en mois)

Description de l'offre

Open in the METRIC lab, the offered position will primarily consist in fulfilling the tasks of the M-One project, centered around the development of a head coil at 7T :

1. Take active part in the design of a 32-channel receive coil insert with the support of a PhD student. The foreseen solution is a tight loop array based on preamplifier-decoupling, but coaxial high-impedance resonators could also be studied to allow for flexibility in a wearable hood or cap. Novel initiatives are welcome, especially if they can also apply at 11.7T. Moreover, the candidate is expected to miniaturize the electronics into a single ~1-cm2 chip encompassing the following functions:

 Transmit/Receive switch: during transmission, the resonator must be detuned, whereas at reception, the NMR signal must be pre-amplified

 Pre-amplification of the NMR signal by field effect transistor

 Impedance matching circuit between coil and transistor. Ideally, one would like to integrate the possibility of automatic adjustment of the resonant frequency and impedance matching, perhaps by means of DTCs (Digitally Tunable Capacitors).

The challenge is to achieve a non-magnetic RF component that supports very high fields and fast gradient switching (which can induce eddy currents). In particular, it is important to consider the disturbance of the Hall effect linked to the static field on the transistor. A packaging of the integrated component in a shielded "cage" will be studied. The targeted frequency is 300 MHz at 7T, but the design of yet another chip working at 500 MHz should also be considered for 11.7T. Consulting with electronic experts from CEA/LETI will be expected from the candidate.

2. Take part in the validation of the final prototype with the help of NeuroSpin MRI experts. Essential steps will include:

 B1-field mappings of a phantom with known electric properties in the 7T-MRI, to be compared with electromagnetic simulations performed in the design stage.

 Prediction of global and maximum local SAR from such simulations + matching of such predictions with PRF-based temperature mappings.

 In-vivo performance measurement: noise correlation matrices, Signal-to-Noise Ratio and g-factor mappings.

 Benchmarking : comparing performance with other commercial coils.

Moreover, the successful candidate will be encouraged to participate in the development of related projects in the MRI instrumentation team.

Desired profile

Profil du candidat

 M.Sc. or Ph.D. in physics or electrical engineering, with a major/minor in microelectronics and Radio-Frequency electronics.
 Experience in MRI RF coil development, or in electronic integration and packaging.
 Excellent skills in analog electronics, including proficient programming with EDA software such as Proteus.
 Some knowledge in MATLAB, Scilab or Python scientific programming is expected.
 Knowledge in CAD software such as Solidworks is a plus.
 Excellent communication, teamwork and organizational skills.
 Excellent knowledge of English is a must. French is appreciated.

Offers “CEA”