Institute for Electronic Structure Dynamics
IRIS Beamline at BESSY II Storage ring
Introduction
The infrared beamline IRIS at the BESSY II storage ring was inaugurated in 2001 and it is currently the only infrared beamline available in Germany for national and international user groups. The design of the beamline allows to extract broadband high-brilliance radiation spanning from 2 to 10000 cm-1. In combination with the top-up operation mode of the BESSY II storage ring, this turns the beamline into a stable radiation source that is well-suited well for a diverse range of different IR-spectroscopy applications.
Optical design
A slotted mirror (M1) is used to extract the optical radiation originating from the homogeneous region of the bending magnet. After the optical beam is refocused twice with two sets of cylindrical mirrors (M2-M3 and M4-M5), and then is collimated by a toroid mirror (M6). The back end and the end stations are separated from the UHV front end of the beamline, providing great flexibility in the redistribution of the synchrotron radiation and modification of the end stations. The collimated beam is delivered to the different end-stations installed at the beam-line.
Outline of IRIS beamline at BESSY II storage ring and the list of the end-stations available for the user operation.
The optical scheme extracts the infrared beam upwards to the top of the storage ring. The beamline provides now four optical ports: three ports on the roof ( ports 1, 2, and 4) and one additional at the ground level (port 3). These ports accomodate 4 different end-stations available to the users of the beam-line:
- Port 1: Infrared spectroscopy based on Bruker 70V vacuum FTIR spectrometer
- Port 2: Single-shot time-resolved spectroscopy based on a FERY-prism dispersive IR spectrometer
- Port 3: Infrared micro-spectroscopy, based on Hyperion 3000 IR microscope
- Port 4: Infrared nano-spectroscopy and imaging based on neaspec scattering type scanning optical microscope (s-SNOM)
The end-stations coupled to the broadband high-brilliance synchrotron radiation source enable improved characterization of molecules and materials at different length scales and time resolutions.
Key Advantages of Synchrotron IR Spectroscopy
- Broad Spectral Coverage
Synchrotron IR sources often span a wider range of the infrared spectrum, from near- to far-infrared. This broad range allows to study many different vibrational modes in a single measurement.
- High flux in THz and far-IR regions
The IRIS beam-line synchrotron radiation is far surpassing thermal (globar) IR sources in tabletop instruments in the far-IR spectal range, that directly translates to improved signal-to-noise ratio for the experiments in the range of 10 - 600 cm -1
- Unmatched Brightness and Intensity
A synchrotron produces IR light that is orders of magnitude brighter than conventional sources. This is vital for micro- and nano-scale IR spectroscopy and imaging, enabling high spatial experiments in a very broad spectral range .
- In Situ and Time-Resolved Studies
With advanced sample environments (temperature, pressure, humidity) it is possible to study materials and reactions as they happen, including real-time chemical changes in biomolecules, temperature induced phase-transitions, or biological samples in native aquaous enviroment.
References
- Peatman, W. B. & Schade, U. (2001). Review of Scientific Instruments 72, 1620–1624.
- Schade, U., Röseler, A., Korte, E. H., Bartl, F., Hofmann, K. P., Noll, T. & Peatman, W. B. (2002). Review of Scientific Instruments 73, 1568–1570
- Veber, A., Puskar, L., Kneipp, J. & Schade, U. (2024). J Synchrotron Rad 31, 613–621.