A COMPUTER-INTERFACE FOR DATA-ACQUISITION FROM A PULSED NUCLEAR-MAGNETIC-RESONANCE SPECTROMETER

A interface is described for rapid data acquisition from a pulsed nucl ear magnetic resonance (NMR) spectrometer. The system is built using a n IBM compatible PC/XT and a commercial data acquisition card. The com puterization has been accomplished without making any changes in the c ommercial spectrometer. The data acquisition program is written in Bas ic using the driver routines supplied along with the data acquisition cal T1 evaluation consists of measuring the FID signal intensities for various values of tau ranging from 10 msec to about 2.5 times the exp ected T1 value. Measurements of T1 can also be carried out by using th e inversion recovery pulse sequence 180-degrees x-tau-90-degrees y6. T ransverse relaxation time (T2) is measured using the Carr-Purcell-Meib oom-Gill7,8 pulse sequence ees)y-2tau-(180-degrees)y-2tau-(180-degrees )y..... The intensities of the spin echoes following each 180-degrees pulse are measured by A/D converter. The trigger for the A/D converter is provided by the spectrometer at the peak of each spin echo. The si gnal intensities for both T1 and T2 measurements are averaged over a n umber of times to improve the signal to noise ratio.