SIMULTANEOUS MEASUREMENT OF ABSORPTION AND CIRCULAR DICHROISM IN A SYNCHROTRON SPECTROMETER.

John Clark Sutherland, Peter C. Keck, Kathleen Pietruszka Griffin, Peter Z. Takacs

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

We describe a method for simultaneously measuring the absorption spectrum and circular dicroism (CD) of a sample in a spectrometer that employs a transparent window photomultiplier detector. During the spectral scan, the computer control system simultaneously monitors the CD signal, the high voltage applied to the detector and the current in the storage ring. A servo-control system maintains the detector current at a constant value during the scan by varying the applied high voltage. The logarithm of the photomultiplier gain is calculated from the value of the high voltage using the predetermined characteristics of the tube. The gain value is corrected for the decrease of the storage ring current with time. During a single spectral scan, the computer generates a pseudo-absorption spectrum, which is the sum of the absorbance of the sample and of various wavelength-dependent system parameters. An absolute absorption spectrum is produced when the pseudo-absorption spectrum of a "blank" sample is subtracted from the desired sample spectrum. Absorption spectra measured by this method agree with spectra obtained with a double-beam spectrophotometer.

Original languageEnglish (US)
Pages (from-to)375-379
Number of pages5
JournalNuclear Instruments and Methods
Volume195
Issue number1-2
DOIs
StatePublished - Jan 1 1981
Externally publishedYes
EventProc of the Natl Conf, 2nd - Ithaca, NY, USA
Duration: Jul 15 1981Jul 17 1981

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ASJC Scopus subject areas

  • Engineering(all)

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