Can we go beyond Blochs spin polarization rate to access spins in fast moving fluids? Due to the difficulties of generating large magnetic fields and the troubles of CFD, this is a potentially high impact solution in flow-NMR.
Aligning spins to a magnetic field
|The problem is as simple as it is hard to solve; the polarization time of a spin is usually between 0.5-4s and magnet lengths are in the cm range, meaning any spin moving above cm/s, will have a small polarization and thus give unacceptably low sensitivities. Despite NMRs powerful and versatile techniques, the end bottleneck is always a low SNR of the measurement. This is due to the magnetic energy being small compared to thermal fluctuations. In addition to this limitation, the slow alignment of the spins to the stable value can produce flow signals 10-1000 times smaller than usual, meaning a measurement time 102 - 106 times larger.|
The objective of this project is to create a pre-polarizing unit to be attached to a commercial NMR sensor currently being developed. It must be fully shielded, in two different geometries, and consist of commercial neodymium magnets and flow control elements. The first implementation has been conceived in-house and should have a straightforward implementation. Posteriorly, other experiments will need to be developed to test approaches put forward in the literature and those suggested by the student. Due to the nature of the work, more details can be discussed with the contacts below. A successful completion of the project will result in a publication or patent.
Type of work
The project is a practical application of physical phenomena and their application in commercial mm-size devices.
- FEM simulation of the magnetic field in COMSOL, for strength optimization.
- Development and assembly of a flow controller based on non-magnetic valves.
- Testing of other EM techniques for magnetic polarization rate improvement.
Starting date: on appointment
Contract duration: 6 months
- Familiarity with running experiments and iterating prototypes accordingly.
- Capable of working independently, being self-motivated and reliable.