Experimental design and methodology for a new Mössbauer Experiment: Absorption Line Tracking

A. VEIGA; G. A. PASQUEVICH; P. MENDOZA ZÉLIS; F. H. SÁNCHEZ; M. B. FERNÁNDEZ VAN RAAP; N. MARTÍNEZ.

Indian Institute of Technology, Kanpur, INDIA,

Congreso; International Conference on the Applications of the Mössbauer Effect.; 2007

In this work we introduce a new experimental setup developed in our lab, along with a methodology which allows the tracking of an absorption line as its energy position varies during the experiment. This device shifts the energy region of interest (ROI) using a versatile and modifiable interacting algorithm. In this way the absorption line position is tracked as a function of an external parameter (temperature, pressure, magnetic field, degree of a solid state reaction advance, etc.), and the evolution of a quantity of interest is measured (e.g.  the dependence of Bhf on T in FeSn2, see Fig. 1). The experimental setup uses a conventional pulse height detection branch (proportional counter, preamplifier, amplifier, single channel) and a driving standard branch (motor and driver CMTE). A programmable constant-velocity scaler PCVS replaces the multiscaler [Veiga et al], see Fig.2. A PC hosting the intelligent algorithm interacts with the device. Based on initial parameters, it establishes a set of source-absorber relative velocities (ROI) and habilitates the PCVS for recording gamma ray transmission within this ROI. Preliminary tests were performed on simulated experiments. As a final test the temperature dependence of the 57Fe hyperfine field in FeSn2 was determined. To this end the temperature evolutions of the first and sixth spectral lines of FeSn2 between RT and its Nèel temperature (» 383 K) were tracked.