Scanning multichannel spectrometry using a charge-coupled device (ccd)

Abstract

A spectrometer using a CCD array in the time-delay integration mode is claimed. The spectrometer comprises a CCD having a plurality of charged-coupled devices disposed along a scan dimension which terminates at an output end of the CCD. Each device produces an electronic charge in response to electromagnetic radiation incident thereon. A monochromator, optically aligned with the CCD, has a diffraction grating which generates a plurality of spectral beams from an external source of electromagnetic radiation. The diffraction grating is movably mounted to sequentially scan the plurality of spectral beams. A control unit, coupled to the monochromator, controls the scanning operation of the diffraction grating and determines a scan rate for the spectral beams. The spectral beams are scanned along the scan dimension of the CCD during the scanning operation. A clock source, coupled to the CCD, sequentially shifts the electronic charge from one charge-coupled device to another along the scan dimension of the CCD at a shift rate substantially equal to the scan rate of the spectral beams. A serial shift register, coupled to the output, end of the CCD, accumulates the electronic charge as it is shifted to the output end of the CCD. An output amplifier, coupled to the shift register, produces a video signal from the electronic charge accumulated in the serial shift register. Each produced video signal represents an intensity value for a respective spectral beams.