Figure 1. Optical scheme of the beamline
The infrared beamline SISSI (Source for Imaging and Spectroscopic Studies in the Infrared) at Elettra extracts the IR and visible components of synchrotron emission for applications of spectroscopy, microspectroscopy and imaging. The applications cover a wide range of research fields, including surface and material science, biochemistry, forensics, microanalysis, geology, cell biology, biomedical diagnostics, microfluidics, time resolved IR, conservation science, protein folding, chemical kinetics.
More details on the beamline, available instrumentation and research activities, can be found at the SISSI beamline webpage.
The radiation is collected from bending magnet 9.1 over acceptance angles of 70 mrad (H) and 25 mrad (V) and comprises both edge and constant field emission. A set of ellipsoid and plane mirrors delivers the light to the instrumentations (Figure 1), consisting in a Michelson interferometer and a confocal infrared microscope.
Figure 1. Optical scheme of the beamline
The interferometer is equipped to analyze and process radiation in the spectral range from about 5 cm-1 to 50000 cm-1. Beamline throughput effectively limits the range to 25000 cm-1. Fast scan and step scan capabilities allow the study rapidly evolving systems, with a time resolution in the range from nanoseconds to milliseconds.
The nanosecond response of the spectrometer and the pulsed nature of synchrotron infrared emission allow the implementation of pump-probe experimental geometries. The pump beam can be provided by either a synchronized external laser source or the synchrotron emission itself, and the probe beam is provided by the beamline emission.
The microscope operates under diffraction limited conditions when used in conjunction with synchrotron light emission and allows spatial resolution of details in the µm range. Moreover, the instrument is equipped with a motorized x-y scanning stage and allows both transmission and reflection measurement geometries. It is configured for fluorescence detection, allowing the sequential acquisition of confocal scanning fluorescence and IR images on the same sample.
Beamline commissioning shows that a significant gain in signal to noise can be appreciated for apertures of 50 microns or smaller when compared to globar illumination.
| Aperture (microns) | N/S (rms) Synchrotron | N/S (rms) Globar |
|---|---|---|
| 2x3 | 0.85 % | 21 % |
| 4x4 | 0.35 % | 3.0 % |
| 5x5 | 0.37 % | 3.0 % |
| 6x6 | 0.22 % | 1.4 % |
| 8x8 | 0.21 % | 0.89 % |
| 10x10 | 0.24 % | 0.59 % |
| 15x15 | 0.19 % | 0.42 % |
| 20x20 | 0.20 % | 0.25 % |
Signal over noise ratio for different apertures of the Hyperion 2000 microscope blades.
The brightness of the synchrotron emission provides mid-IR spectra from v=6000 cm-1 (v=1.6 microns) to v=800 cm-1 (v=12 microns) of objects with a size of 4x4 microns.
The figure below represents the result of a linear scan of a patterned target. The brightness of the emission allows determining the position of an object with a precision of 1 micron by frequency-dependent reflection contrast in the mid- and near-infrared range. Absorption based contrast has been achieved on real samples down to a few micrometer spatial resolution.
Figure 2. Spectral plots as a function of position for a linear scan of a target pattern.
| Energy Range | 10-25,000 cm-1 (1 meV-3eV) |
|---|---|
| Space Resolution | Diffraction limited |
| Energy Resolution | 0.2 cm-1 |
| Time Resolution | ~1 ns (step-scan mode); ~1 msec (slow-scan mode) |
| Configuration | Transmission, Reflection, ATR |
| Additional Features | Fluorescence Imaging Experiments in High Magnetic Fields |
| Interferometer | Bruker IFS 66v/S |
|---|---|
| Microscope | Bruker Hyperion 2000 |
Under final commissioning
AN INFRARED SYNCHROTRON RADIATION BEAMLINE AT THE THIRD GENERATION LIGHT SOURCE ELETTRA
A. Nucara, S. Lupi, and P. Calvani
Submitted to Review of Scientific Instruments (2002). (
pdf, 1,6MB)
FIRST OBSERVATIONS OF INFRARED SYNCHOTRON RADIATION AT ELETTRA
S. Lupi, A. Nucara, P. Calvani, and M. Ferianis
Synch. Rad. News, 14, 32 (2001). ( pdf, 56KB)
THE SYNCHROTRON INFRARED BEAMLINE SISSI AT ELETTRA
A. Nucara, S. Lupi, and P. Calvani
Infrared Physics & Technology, 45, 375 (2004).
Diane Eichert
phone : ++39 040 375 8729
fax: ++39 040 375 8776
email: diane.eichert@elettra.trieste.it
Lisa Vaccari
phone : ++39 040 375 8465
fax: ++39 040 375 8776
email: lisa.vaccari@elettra.trieste.it
Stefano Lupi
phone: ++39 06 4991 3496 (507)
fax: ++39 06 4463 158
email: stefano.lupi@roma1.infn.it
Andrea Perucchi
phone: ++39 0403758728
fax: ++39 040 375 8776
email: andrea.perucchi@elettra.trieste.it