A Basic Mossbauer Spectrometer Set-Up

A basic Mossbauer spectrometer set-up (Fig. 4.8) consists of a Co radioactive source mounted on a velocity transducer (drive unit), where it is repeatedly moved between zero and maximum velocity (typically a triangular wave of frequency 10-20 Hz), and a proportional counter, giving an absorption spectrum in the multichannel analyzer (MCA). 

Mossbauer measurements are generally performed to analyze the samples containing iron. For this purpose, one uses a specially prepared Mossbauer source of 10-20 mCi (usually Co diffused into Rhodium or Palladium foil) which emits the 14.4 keV photon by excited Fe nuclei produced by the (3-decay of Co. Some of the 14.4 keV photons are emitted by nuclei that share the recoil momentum with macroscopic bits of the matter in which they are imbedded ( recoilless emission ) with the result that their fractional spread in energy, or line width AE/E is extraordinary narrow, of the order of 10 . A sample containing Fe-atoms in an environment that permits recoilless absorption of 14.4 keV photons, is placed between the source and the proportional counter. The sample of iron or compoimd of iron, which should be a thin foil (less than 20 pm), is placed at a distance of 5-10 cm from the Mossbauer source. 

The motion of the Mossbauer source causes a corresponding sawtooth Doppler shift in the energies of the photons that traverse the sample. In effect, the narrow emission line is swept back and forth in energy over the recoilless 

User-friendly Mossbauer spectroscopy oriented analyzer card (MSPCA) with the standard software, the details of which can be found from the website http //alag3.mfa.kfki.hu/magnet/mossba/index.htm, can be used to transform the personal computer into a full-featured Mossbauer spectroscopy analyzer. Any type of the Mossbauer function generators and driving units can be connectable to this analyzer card. The card is coimectable to a Per- 

Converting Velocity into Channel Number by Multichannel Analyzer 

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