Smooth driving of Mössbauer electromechanical transducers

Abstract

Quality of Mössbauer spectra is strongly related to the performance of source velocity modulator. Traditional electromechanical driving techniques demand hard-edged square or triangular velocity waveforms that introduce long settling times and demand careful driver tuning. For this work, the behavior of commercial velocity transducers and drive units was studied under different working conditions. Different velocity reference waveforms in constant-acceleration, constant-velocity and programmable-velocity techniques were tested. Significant improvement in spectrometer efficiency and accuracy was achieved by replacing triangular and square hard edges with continuous smooth-shaped transitions. A criterion for best waveform selection and synchronization is presented and attainable enhancements are evaluated. In order to fully exploit this driving technique, a compact microprocessorbased architecture is proposed and a suitable data acquisition system implementation is presented. System linearity and efficiency characterization are also shown.

Enhancing vibration measurements by Mössbauer effect

“…A multichannel scaler (MCS) designed in our laboratory [10] was used as wave reference generator for the PD excitation and as a multiscaler for the data acquisition. With this custom equipment, frequencies up to 75 kHz can be reached when only four acquisition channels are used.…”

Influence of Nb Doping on Magnetic Properties of Nanocrystalline Nd-Fe-B Alloys

“…The Mössbauer measurements were recorded at room temperature (RT) under transmission geometry with a standard constant acceleration spectrometer, using a 5 mCi CoRh radioactive source. Data was recorded using a 1024 channel MDAQ107 data acquisition module [10]. The isomer shifts were referred to RT -Fe.…”

Digital pulse processing in Mössbauer spectroscopy

“…The same detector (Wissel LND-45431) and bias (2 kV) were used in all the experiments. The Mössbauer spectrometer was completed with a 57Co source mounted on MA250 transducer driven by MR350 unit (Wissel) and a programmable MDAQ208 module [15,16] performing as constant-velocity multichannel scaler. The same calibration absorber was used in all the experiments (α-Fe 12 μm iron foil) in transmission geometry.…”