Double Moessbauer spectrometer for measurements of resonance line low shifts

A block-diagram of a Moessbauer spectrometer for precision measurements of small shifts is described. The spectrometer can effect coincidence in time of the sample spectrum and a reference spectrum. The matching accuracy is determined by the analyzer bandwidth. The matching of spectra allows to eliminate the effects of apparatus parameter instabilities on measurement results. The principal diagram of analyzer band selector and its function are described. The sample temperature is stabilized by a device which ensures the control accuracy of not worse than +-10-2 K. The paired Moessbauer spectrometer design described may be used in any precision small shift measurement applications. The measurement accuracy for 57Fe and 119Sn isotopes is not worse than 10-3 mm/sec