Mössbauer Spectrometers

The Mössbauer spectrometer uses a radioactive ⁵⁷Co source to generate gamma rays that are absorbed by ⁵⁷Fe in a sample. The nature of absorbtion by the ⁵⁷Fe is a function of the valence state and type of bonding in an Fe-mineral's lattice, and so the Mössbauer effect can be diagnostic of magnetic Fe sulfides and oxides.

A more detailed description can be found in IRM Quarterly v. 2, n. 3, Fall 1992.

SEE Co. MS4 Mössbauer spectrometer, with Lake Shore (Janis) CCS-800 Mössbauer Refrigerator System

Specifications:

• Temperature range: 2K - 300K
• Applied Field: 0 T 
• Measurement time: several hours

SEE Co. MS6 Mössbauer spectrometer, with Janis SVT-400 Nitrogen-shielded liquid Helium cryostat

Specifications (LT, high-Field):

• Temperature range: 2K - 300K
• Measurement time: several hours

Additional equipment:

• Janis liquid helium cryostat with superconducting magnet, 4.2K - 300K, 0 - 6.5 Tesla

Mössbauer Sample Prep:

The standard Mössbauer sample holder is a small pair of nesting Delron cups that are 12.7 mm in diameter and 10 mm deep, and powdered samples are pressed between the two cups. Samples are often dispersed in Boron Nitride or Spectroblend, or other non-magnetic low atomic weight material. In general, smaller amounts of sample with higher concentrations of Iron work best, if the sample is too thick it will absorb most of the gamma rays preventing a reasonable count rate at the detector.