Engineer/scientist position at CEA/NeuroSpin (2020-22) in
RF electronics for MRI at Ultra-High-Field
Description of the position
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.
More details on Neurospin, BAOBAB unit, METRIC Lab, M-One project and required qualifications in the .Pdf ⇒ M-One position at CEA NeuroSpin
Application
The position is open at CEA for 2 years as early as possible from October 1, 2020.
We look forward to receiving your online application before June 30, 2020, with
1- a cover/motivation letter (one page) that demonstrates your suitability for the offered position,
2- a curriculum vitae including a list of publications and academic records,
3- names and contact information of two references.
Contact : Send all documents to alexis.amadon@cea.fr and alexandre.vignaud@cea.fr
