Instrumentation
At the far-IR (FIR) beamline of the AS, edge radiation (ER) is collected from a dipole bend magnet and directed into a Brüker IFS 125/HR Fourier Transform (FT) spectrometer. ER is more intense than normal bending magnet synchrotron radiation (BMR) and has a more intense far-IR component. It is also radially polarised instead of elliptically polarised.

The Brüker spectrometer utilises a Michelson interferometer with an optical path length of 942 cm for single-sided data acquisition Optics: f/6.5. This instrument has three internal light sources: Hg-Arc lamp, 5-1000 cm^-1; Globar source, 10-13000 cm^-1; Tungsten lamp, 1000-25000 cm^-1. The spectrometer is also equipped with an array of optical filters, detectors and beamsplitters offering continuous spectral coverage from the THz to the mid-IR regions.

The instrument can be connected to a multitude of accessories and components via the sample compartment, allowing a variety of gas and condensed phase experiments to be conducted. The sample compartment can be evacuated and vented independently from the rest of the spectrometer which makes sample changes more rapid. Please see Samples for more information regarding available sample mounts. The IFS 125/HR spectrometer is generally operated under vacuum conditions but the sample compartment can be purged with nitrogen gas if required. The spectrometer is remotely controlled using the OPUSTM software v.6.5.

The Brüker IFS 125/HR Fourier transform IR spectrometer coupled to the IR beamline at the Australian Synchrotron.

Energy Range, Detectors & Equipment
The FIR & HR IR beamline is equipped with a number of different detector types, allowing sample analysis across a wide spectral range.

Table 1. Available Detectors

Table 2. Beamsplitters

Table 3. Light Sources

A series of narrow band pass IR Optical Filters are also available to reduce the bandwidth (and thus the noise), and apertures ranging from 0.5-12 mm can be used to reduce the beam diameter.

Beamline Performance & Calibration

Rotationally resolved spectra of a gas sample recorded at 0.001 cm^-1 resolution.

The blue scan used a conventional thermal while the scan in red was taken using synchrotron radiation. The S/N obtained with the synchrotron is superior to that of a conventional thermal source by a factor of approximately 60.