In studies of the transport in porous materials it is important to
measure concentration profiles of moisture and ions
non-destructively. Nuclear Magnetic Resonance (NMR) is a powerful
technique to measure the time evolution of e.g. moisture profiles
with a high spatial resolution. However, many technological porous
materials contain large amounts of para-magnetic ions, which
complicates the NMR measurements. Therefore the moisture transport
is studied using specially developed NMR scanners which have
the possibility to measure quantitative using a Faraday shield. Here
a short overview is give of the instruments and the main
characteristics
1.5 T - 60 Mhz (Philips)
3D medical imaging
insert high temperature >300oC,
grad 0.3 T/m
H/Na imaging
4.7T - 200 Mhz
digital
NMR (Spincore based)
1D,
grad 0.6 T/m max grad
H, Li, Na, Cl imaging
0.7 T - 31 Mhz
digital NMR (Spincore based)
1D,
grad 0.6 T/m max
H-imaging
0.8 T - 33.1 Mhz
digital
NMR (Spincore based)
1D, grad max 0.3 T/m
H/Na imaging
0.7 T - 30 Mhz
digital NMR (Spincore based)
2D, max grad 0.3 T/m
H, Na, Li imaging
0.8 T - 34 Mhz
digital NMR (Spincore
based)
1D, max grad 0.4T/m
H, Li, Na imaging
1.5 T - 60 Mhz
analog NMR
1D, grad 36 T/m continuous
H imaging
1.5 T - 60 Mhz
analog NMR
1D, grad 40 T/m continuous (resolution
~10 µm)
H imaging