Single photon spectrometer

Abstract

A fiberized single photon sensitive spectrometer on a 32-channel PMT sensor is highly sensitive with broad detection dynamic range. The spectrometer enables accurate and high speed detection, identification and analysis of biological samples labeled with multiple fluorescent markers, such as compositions of multi-color fluorescence signals or radiation emitted by multiple fluorescence dyes. A fiberized optical input of the spectrometer allows an easy and efficient coupling to any measurement system based on fiber collection of the analyzed fluorescence. The spectrometer provides highly accurate DNA sequencing. A 32 channel PMT single photon detector has a detection dynamic range of more than 20 bits and has a frame rate of about 3300 frames per second. The dynamic range of the detector's pixels reaches 10 8 photocounts per second.

1 .- 24 . (canceled) 
     
     
         25 . A method for identifying DNA sequences comprising the steps of:
 Labeling selected DNA fragments with fluorescent dyes;   Inputting said DNA fragments to an optical fiber separation capillary;   Illuminating said labeled DNA fragments in said optical fiber separation capillary with laser light of a predetermined wavelength to produce fluorescence spectra from said DNA fragments;   Illuminating optical fiber with the fluorescence spectra from said DNA fragments, said optical fiber conveying said fluorescence spectra to a light spectra separator, the output from said light spectra separator being incident upon at least one multichannel photosensor, each photosensor channel having photosensitive pixels adapted receive distinct light spectra from said light spectra separator and to produce current pulses in response to single photons of each different wavelength of said distinct light spectra.   
     
     
         26 . The method of  claim 25  in which said laser light is produced by lasers selected from the group of Ar-ion and Nd:YAG lasers, the wavelengths of said lasers being within the range of from 488 nm to 532 nm. 
     
     
         27 . The method of  claim 25  in which said predetermined wavelengths are one of 488 nm, 514 nm and 532 nm. 
     
     
         28 . The method of  claim 25  in which said optical fiber separation capillary has a core diameter of about 200 micrometers. 
     
     
         29 . The method of  claim 25  comprising the step of electrophoretically separating said DNA fragments in said optical fiber separation capillary. 
     
     
         30 . The method of  claim 25  in which said at least one multichannel photosensor comprises a linear photo multiplying tube array of 32 channels. 
     
     
         31 .- 32 . (canceled)