Influence of Magic Angle Spinning on Sample Temperature

Abstract

Magic angle spinning at sufficiently high rates dramatically changes the sample temperature. A method is described for calibrating a probe head for the thermal effects encountered during magnic angle spinning experiments. Using Sm2Sn2O7 as a chemical shift thermometer, the overlapping effects of ‘external’ heating or cooling by the bearing gas and ‘internal’ heating by friction on the actual sample temperature were studied. The empirical expression Ts=0.12νr2+(3.47-0.013Tb)νr+0.80Tb+58.6 describes the influence of the bearing gas temperature Tb (K) and the spinning rate νr (kHz) on the sample temperature Ts (K). © 1997 by John Wiley & Sons, Ltd.