SPRITE, 1 dimensional

Fig. 3.4.2 Schematic description of the three-dimensional SPRITE imaging technique. Gz, Gx and Gy are the phase encode magnetic field gradients and are amplitude cycled. A single data point is acquired at a fixed encoding time tp after the rf excitation pulse from the free induction decay (FID). TR is the time between rf pulses. Notice that Gx is ramped (+GZ max to -GXt max) and one /c-space point is acquired for each value of the magnetic field gradient. Gy and Gz are on during the Gx magnetic field gradient ramp and turned off at the end.

Fig. 3.4.3 (a) Two-dimensional k-space acquisition using SPI or SPRITE. The k-space data acquisition is indicated numerically. High magnetic field gradient amplitudes are applied at the extremities of k-space. (b) A generic two-dimensional centric scan SPRITE method. The... 

Fig. 3.4.4 Schematic description of the one-dimensional double half k (DHK) SPRITE technique. The phase encode magnetic field gradient, Gz, ramped through half of /(-space beginning at the center and a single data point is acquired at a fixed time (tp) after the rf excitation pulse. The second half of /(-space is acquired after a 5T time delay. The time between rf pulses is TR.

Fig. 3.4.9 Two-dimensional slice images taken from a three-dimensional Spiral-SPRITE water uptake experiment [27]. (a) Initially dry,...

Fig. 3.4.14 One-dimensional SPRITE image of the sodium distribution in mortar specimens...

The centric scan, one-dimensional, DHK SPRITE measurement was used to study the ingress of lithium. This measurement technique was selected due to the low absolute sensitivity of 7Li (27% of [36]), the small amounts that are present and the short signal lifetimes (bulk Tx of 10 ms and T2 of 120 ps). In addition to the robust, quantitative nature of this technique, lithium is a quadrupolar nucleus and interpretation of the image intensity is more complex than spin % nuclei. Once again Eq. (3.4.2) is quantitatively correct for even quadrupolar nuclei due to the fact the longitudinal steady state does not influence the image intensity. 

Figure 3.4.16 shows one-dimensional DHK-SPRITE profiles of lithium penetrating into dry mortar. In addition to the determination of the penetration depth of lithium shown at various times, there is an overall increase in signal intensity at a given point, which is attributed to the filling of the various pore sizes in time. The... 

Fig. 4 Mapping coke distribution with the SPRITE technique (21). (a) Photograph of the sample used for the study. Two layers of coked HZSM-5 (areas a) were separated by a layer of fresh HZSM-5 (area b). Each layer was about 3.3 cm in length, (b) One dimensional SPRITE profile for the sample shown in (a).

Fig. 2. Two-dimensional SPRITE sequence. The primary phase encode gradient is stepped between discrete values as a function of the secondary phase encode gradients (one shown). The encoding time is tp, the repetition time is TR. A single point is acquired at each gradient value. (After Balcom." )...

This section discusses 3D-SPRITE which has been shown to be successful for studying short relaxation time systems and which is free from distortions due to susceptibility variations for coals with high resolution at a frequency of 400 MHz.55 The results obtained are discussed in relation to the three-dimensional distribution of the mobile component for two kinds of coal, Witbank and Goonyella. At the same time, inversion recovery preparation experiments (7 mapping), T2 mapping and T mapping based on SPRITE methods are presented in order to clarify the chemical heterogeneity of coals. 

Figure 1 The one-dimensional DHK-SPRITE sequence. The magnetic field gradient (G2) is ramped linearly in steps to +G in the half of the measurement and to...

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