Article ID Journal Published Year Pages File Type
1686539 Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2011 5 Pages PDF
Abstract

In-beam Mössbauer spectroscopy utilizing unstable 57Mn beams is a powerful method to extract physical and chemical properties at the atomic scale. A parallel plate avalanche counter (PPAC), optimized to detect conversion electrons generated by the Mössbauer effect, can be employed to suppress higher-energy background γ rays. However, β rays are emitted by the 57Mn parent nuclei of 57Fe, which can significantly degrade the spectrum quality. In the present work, we have developed a new anti-coincidence-detection system with a thin plastic scintillation counter (0.5 mmt), which can be used to detect β rays and reject them from the recorded PPAC events. To demonstrate the anti-coincidence system, we carried out Mössbauer spectroscopy utilizing 57Mn nuclei that were implanted into a non-magnetic aluminum metal plate at room temperature. Using the anti-coincidence method, we obtained a typical Mössbauer spectrum of high quality, despite a very low number of implanted 57Mn atoms, of ∼5 × 109. The signal to noise ratio of the obtained spectrum was increased remarkably, and the relative peak height above the baseline increased from 10% to 220% using the anti-coincidence method. The developed detection system is applicable to investigation of in situ properties, and avoids the potentially problematic agglomeration of probes in a sample.

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Physical Sciences and Engineering Materials Science Surfaces, Coatings and Films
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