Operation of a cryogenic conversion electron proportional counter for Mössbauer spectroscopy

The use of He-filled proportional counters for CEMS studies with⁵⁷Fe is very attractive because of their high efficiency. Stability problems at low temperature have been solved by using an electronic feed back which controls the anode voltage to keep the gas gain constant. Long term stable operation has been achieved between 370 K and 50 K. The potential of the counter is demonstrated on epitaxial and amorphous magnetic thin films.