Hyperfine Interactions 57 (1990) 1889-1900 Criteria for optimizing DCEMS Zs. Kajcsos, Ch. Sauer, and W. Zinn As depth-selective conversion electron Mössbauer-effect measurements present a difficult task in Mössbauer spectroscopy due to the long recording times involved, the shortening of the measuring times is of major practical importance. Possible improvements of the overall experimental performance and measuring time gains due to efficiency increase and background reduction will be analyzed; advantages of scintillation counter over a channeltron for ^{57}Fe DCEMS applications will be discussed.