2D backscattering Mössbauer measurements with MIMOS II

Abstract The miniaturised Mössbauer spectrometer (MIMOS II) is continuously developed at the Leibniz University Hannover in collaboration with the Hannover University of Applied Sciences and Arts. The former MIMOS II processing unit can no longer be manufactured because some necessary components are not available anymore. Building on our previous work, which introduced a new processing unit with Arduino-based two-dimensional (2D) data acquisition that allowed the operation of the MIMOS II hardware (including the drive and one detector), we have now further developed the hardware and software. This further development makes it possible to operate the entire MIMOS II sensor head with four backscattering detectors and one transmission detector simultaneously. The 2D data processing simplified the data acquisition without the need for predetermined thresholds. It allows the selection of relevant regions for the Mössbauer spectrum after the measurement. With this approach, it is now possible to measure simultaneously 6.4 keV and 14.4 keV signals of iron-57 for the four backscattering detectors of the MIMOS II sensor head. In contrast, the old processing unit only allowed measurements with either 6.4 keV or 14.4 keV separately for the detectors. Simultaneously measurements of both energies were only possible by adding the counts from the energy ranges of two detectors, which posed a problem if, for example, a malfunctioning detector has a higher noise level.