Characterization of porous media structure by non linear NMR methods.
In this paper we discuss the possibility of modifying the multiple spin echoes existing theory, developed for a homogeneous system, to describe also an inhomogeneous system such as a porous medium. We report here the first experimental application of MSE methods to materials like travertine. The ratio A(2)/A(1) from water in travertine presents minima for characteristic values of the delay time tau, like what was previously observed in the trabecular bone. By a judicious choice of the delay time tau and of the G gradient strength, the MSE sequence can be made sensitive to a specific length-scale of the sample heterogeneity. Furthermore the MSE image shows a particular new contrast that makes the non linear NMR method very attractive for the assessment of variations of the porous structure in porous systems.
Capuani
S
S
Istituto Nazionale Fisica della Materia (INFM) UdR Roma 1 and Physics Department, University "La Sapienza", 00185, Roma, Italy.
Alesiani
M
M
Alessandri
F M
FM
Maraviglia
B
B
D002119:Calcium Carbonate; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D055585:Physical Phenomena; D010825:Physics; D016062:Porosity
D002119:Calcium Carbonate