Electron Spectroscopy Group

 

NSLS Beamline U10A - High Brightness Infrared - Decommissioned.

 

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General Information

• RESEARCH PROGRAM: Wide range, high brightness IR spectroscopy.  Research within the BNL Physics Department deals with condensed matter physics and the optical properties of solids, with particular emphasis on the "bad metals", transition-metal oxides, superconductors and other exotic systems which display evidence of highly-correlated behavior.

• RING: VUV-IR port.

• STATUS: Decommissioned.

• TIME DEDICATED TO NSLS GENERAL USER PROGRAM: None. If you were considering performing experiments at U10A, strong consideration should be given to shifting this work to beamline U12IR. If you would like to learn more about the fundamentals of infrared spectroscopy, you can view a PDF file of a monograph Fourier-transform infrared spectroscopy that I am working on, but have not yet finished (you will need Adobe Acrobat Reader to view this document).

VUV Operating Schedules

Participating Institutions

• BNL Physics Department

• National Synchrotron Light Source

• SUNY at Stony Brook

Local Contact: Christopher Homes - (631) 344-7579, homes@bnl.gov

Spokesperson: Larry Carr - (631) 344-2237, carr@bnl.gov

 

 

Instrument

 

Bruker IFS 66 v/S Fourier Transform Interferometer

 

Instrument and beamline characteristics

• Frequency range (cm^-1): 20 > 25,000

• Resolution (cm^-1): 0.11

• Brightness (relative to 1000K black-body source): 100-1000

• Spot size (f/4, cm): 0.1H x 0.05V

• Total angular acceptance (milliradians): 40H x 40V

 

The Bruker IFS66 v/S is shown above in a reflectance configuration where the beam is drawn out of the instrument.  The transfer optics to guide the light from the synchrotron into interferometer sit just to the right of the instrument.  The U12IR beamline sits behind U10A, and the large magnet that is sometimes used at that end station is shown in the background.  Some more pictures of the instrument and optics developed by the U10A PRT are shown below (click on thumbnail to enlarge).

 

       

 

Optical Configuration

Beamline Optical System

 

A two mirror system (M1 and M2) collects and re-images the synchrotron infrared source at a point just outside of the storage rings UHV.  The M1 mirror is a water cooled plane mirror made from silicon with a gold reflective coating.  The M2 mirror is a glass ellipsoid with a bare aluminum reflective coating.  The ellipsoidal mirror focuses the beam through a 10 mm aperture wedged diamond window (~350 microns thick).  The delivered spectral range extends from approximately 10 cm^-1 to beyond 40,000 cm^-1; the beam is then collimated (aluminized off-axis paraboloid) to the IR spectrometer.  The collimated beam is then refocused into the spectrometer using an off-axis parabolic mirror; this mirror is identical to the mirror used to collimate the light from the internal sources resulting in a symmetric arrangement, allowing the user to change back and forth between sources while the instrument is under vacuum without any loss in alignment.

 

Experimental Apparatus

 

The Bruker IFS66v/S is a Fourier transform interferometer with rapid and step-scan options.  The instrument operates under vacuum for improved performance in the far and mid infrared.  There are three internal sources (Hg arc lamp, GLOBAR, and Tungsten lamp for the far infrared, mid infrared, and visible regions), as well as the broad-band external synchrotron source.  There are a variety of beamsplitters and detectors for the far infrared (4.2K Si:B bolometer & RT DTGS pyroelectric detectors, ~20 to 700 cm^-1), mid and near infrared (4.2K Si:B photoconductor, RT DTGS pyroelectric, and 77K InSb, ~300 to 18,000 cm^-1), visible and UV regions (Si and GaP diodes, 9,000 to over 28,000 cm^-1).  Instrument automation allows the sources, and to a lesser extent the detectors, to be changed while the instrument is  under vacuum.  A feature also exists to extract collimated beam after the beamsplitter through a port on the interferometer bench.

 

Computer System Hardware and Software

 

The interferometer computer is an Intel PentiumII 300 MHz system running Windows 2000.  The data acquisition system is Bruker's OPUS NT software, version 3.1 (build 22).  OPUS for OS/2 is no longer supported on the Bruker spectrometer.  However, an offline OS/2 machine with OPUS 3.0.4 is maintained for users who require the OS/2 operating system for postrun analysis.

 

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Last update on: 10 Jun 2008.