Browse Prior Art Database

Multimode Spectrometer

IP.com Disclosure Number: IPCOM000086506D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 4 page(s) / 45K

Publishing Venue

IBM

Related People

Durham, O: AUTHOR [+2]

Abstract

The drawing shows a multimode spectrometric system operable as a single beam instrument or a double beam instrument to perform many different functions, e.g., the measurement of transmission; straight-through, right-angle and front-surface fluorescence emission; corrected fluorescence spectra by the quantum-counter method; fluorescence normalized to absorbance; fluorescence polarization; fluorescence lifetime; atomic absorption and/or fluorescence with appropriate accessories; arc emission with appropriate accessories; optical rotary dispersion; circular dichroism; polarimetry; and saccharimetry.

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Multimode Spectrometer

The drawing shows a multimode spectrometric system operable as a single beam instrument or a double beam instrument to perform many different functions, e.g., the measurement of transmission; straight-through, right-angle and front-surface fluorescence emission; corrected fluorescence spectra by the quantum-counter method; fluorescence normalized to absorbance; fluorescence polarization; fluorescence lifetime; atomic absorption and/or fluorescence with appropriate accessories; arc emission with appropriate accessories; optical rotary dispersion; circular dichroism; polarimetry; and saccharimetry.

The system includes a light source 1 that may have single or plural standard light sources for conducting the various measurements. The light source may be operated on a continuous, pulse or flash basis to direct light along a reference beam or path 3 and a sample beam or path 4. These paths may comprise fiber- optic light guides for transmitting light, and such other optical elements as are necessary to gather and direct light along the desired paths. Paths 3 and 4 terminate in a diode-array spectrometer that includes some form of a self- scanning photodiode array providing output signals across the bandwidth of dispersed light directed onto the array. This allows the incident light to be analyzed across the bandwidth.

Located along path 4 are a polarizing element 8 and a filter 11 that may be either an exciter filter or a circular variable interference filter, and a sample compartment 12 for receiving the sample to be analyzed. A shutter 13 is movable between two 90 Degrees displaced positions for blocking light along alternate paths 4A and 4B. A sectored optical chopper 14 is driven at a constant speed by motor M and serves to chop the light beams along the paths. Light along path 4A may be directed onto a rhodamine B quantum counter 15 and an absorption detector 16, e.g., a photomultiplier tube or photodiode. An analyzer element 9 is located in the return path of sample path 4.

Located in reference path 3 are a polarizer element 7 and an analyzer element 10. Elements 7-10 are optional and may be switched into and out of their positions in the respective paths. Light from source 1 along the reference path passes through chopper 14. In reference path 3 is a reference compartment 17 placed so that light can be passed to either spectrometer 2 or detector 19. A reference rhodamine B quantum counter 18 is located in front of detector 19 to receive radiant energy from compartment 17.

I. System Operation with a Single-Channel Instrument.

For transmission (%T) or absorbance (O.D.) measurements, a selected spectral source 1 is directed along sample path optical fiber 4 to sample compartment 12. Shutter 13 permits 180 Degrees or 90 Degrees collection of light passed through the sample by blocking in one of its two possible positions. Polarizing element 8 and/or a bandpass filter or monochromator may, optionally, be interpo...