The effect of diffusion in internal gradients on nuclear magnetic resonance transverse relaxation measurements

Journal Article · Wed Nov 13 04:00:00 EST 2013 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4833712· OSTI ID:22257173

Muncaci, S.; Ardelean, I. ^[1]; Boboia, S. ^[2]

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1. Technical University of Cluj-Napoca, Physics and Chemistry Department, Cluj-Napoca (Romania)
2. Technical University of Cluj-Napoca, Physics and Chemistry Department, Cluj-Napoca, Romania and Babes Bolyai University, Raluca Ripan Chemistry Research Institute, Cluj-Napoca (Romania)

In the present work we study the internal gradient effects on diffusion attenuation of the echo train appearing in the well-known Carr-Purcell-Meiboom-Gill (CPMG) technique, extensively used for transverse relaxation measurements. Our investigations are carried out on two porous ceramics, prepared with the same amount of magnetic impurities (Fe{sub 2}O{sub 3}) but different pore sizes. It is shown that diffusion effects on the CPMG echo train attenuation are strongly influenced by the pore size for the same magnetic susceptibility of the two samples. The experimental results were compared with a theoretical model taking into account the limit of free or restricted diffusion on echo train attenuation. The NMR experiments were performed on water filled samples using a low-field NMR instrument. The porous ceramics were prepared using both the replica technique and the powder compression technique. Magnetic susceptibility measurements indicated close values of the susceptibility constant for the two samples whereas the SEM images indicated different pore sizes. The results reported here may have impact in the interpretation of NMR relaxation measurements of water in soils or concrete samples.

• OSTI ID: 22257173
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1565; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CERAMICS
COMPRESSION
DIFFUSION
FERRITES
MAGNETIC SUSCEPTIBILITY
NUCLEAR MAGNETIC RESONANCE
POROUS MATERIALS
RELAXATION
REPLICA TECHNIQUES
SCANNING ELECTRON MICROSCOPY