Gateable CCD Detector for Laser Spectroscopic Identification of Aerosols

摘要

We summarize the new accomplishments that were made possible as a result of theacquisition of two CCD detectors (one gateable CCD detector and one liquid nitrogen cooled CCD detector, both from Princeton Instruments) with one common controller. Progress has been made jointly with Drs. Ronald Pinnick and Steven Hill (of the Army Research Laboratory, WSMR, NM) mainly in the area of fluorescence-spectra determination of single biological airborne particle as the particle flew by the pulsed UV laser focal volume. By using the gateable CCD detector, we have demonstrated the ability to capture the fluorescence spectrum on one type of particle while ignoring others. The decision as to what type of particles to capture the fluorescence spectrum is solely based on the particle fluorescence and/or elastic scattering characteristics. By using the liquid nitrogen cooled CCD detector, we were able to determine, with several UV laser wavelengths (266 nm and 355 nm), the fluorescence spectra of a large number of biological particles in various environments, i.e., whether the biological spores on a glass slide are dry or in an optical cell containing water. Spectral shifts and changes in the fluorescence intensity are noted. The usage of these DURIP-Yale instruments in other DoD sponsored research topics are briefly mentioned.