The all-new GMR Flex Pre-polarization Module provides a controlled and boosted static magnetic field to enable precise, high signal to noise ratio measurement and imaging of water content in the top 3 meters of the subsurface, even when using very small detection loops. The GMR Flex Pre-polarization Module and software also enable effective detection and imaging using small loops in high noise environments.
This technique works by generating a large DC current through a dedicated multi-turn induction coil. This DC current loop generates a large static magnetic field, which increases the polarization and magnetization of water in the ground, enabling up to 10 times higher signal amplitude from water in the top few meters. The pre-polarization current is shut off in a fast and controlled manner, just prior to transmitting the NMR excitation pulse(s).
The GMR Flex pre-polarization can operate from external batteries up to 36V, and has impressive technical specifications that enable fast and precise pre-polarization NMR measurements:
- Shut off time < 1 ms for a 50-turn, 2.5m pre-polarization loop with 25A DC current.
- Hybrid Linear and adiabatic turn off waveform for artifact free measurements.
- Complete inversion including full Bloch formulation that accurately models the effects of the pre-polarization field and its turn off characteristics.
- Compatible with Free Induction Decay (FID), Adiabatic and CPMG pulse sequences.
Depending on specific field conditions, the GMR Flex pre-polarization filter can provide non-invasive measurements in as little as 10 minutes.