Scattered electron Moessbauer measurements at 77.3 K with a He-CO proportional counter

A He-CO proportional counter and a cryostat were designed for measuring scattered electron Moessbauer spectra at 77.3 approximately 293 K. Good scattered electron Moessbauer spectra were obtained both at 77.3 and 193 K in short measuring periods (2 approximately 3 h) owing to high counting efficiencies of proportional counters. The S/N ratio for peaks in CEM (conversional electron Moessbauer) spectra was improved by selecting appropriate energy region of the scattered electrons. With this system, both scattered electron Moessbauer and transmission Moessbauer spectra can be obtained simultaneously. The technique was used for 57Fe-enriched 310 stainless steel foils and Fe2O3. (author)