Fast detectors for M¨ossbauer spectroscopy * ) A.L. Kholmetskii Department of Physics, Belarus State University, Minsk, Belarus M. Mashlan Palack´ y University, Olomouc, Czech Republic K. Nomura School of Engineering, The University of Tokyo, Japan O.V. Misevich, A.R. Lopatik Institute of Nuclear Problems, Minsk, Belarus Received 17 May 2001 The methods to increase the productivity (statistical quality) of M¨ossbauer measure- ments have been considered. Some fast detectors for gamma- and secondary radiation have been described. These detectors allow in many cases to essentially reduce the time for the M¨ossbauer spectra accumulation with a given productivity. 1 Productivity of M¨ ossbauer measurements It is well known (see, e.g. [1]) that the productivity (statistical quality) of M¨ ossbauer measurements is determined by the expression Q = ε 2 ε +2 N (∞), (1) where ε is the value of resonant effect, ε = |N (∞) - N (0)| N (∞) ; N (0) and N (∞) are the numbers of counts in resonance and far from resonance, respectively. In the case of transmission measurements ε is always much smaller than unity, and we can use an approximate relation Q ≈ 1 2 ε 2 N (∞). (2) In order to understand how to increase the productivity Q in practice, it is necessary to express it via the parameters of the M¨ossbauer spectrometer, in par- ticular, the M¨ ossbauer source and the spectrometric section. As a rule, emission ∗ )Presented at the International Colloquium “M¨ossbauer Spectroscopy in Materials Science”, Velk´ e Losiny, Czech Republic, 3–8 September 2000. Czechoslovak Journal of Physics, Vol. 51 (2001), No. 7 763