VERY HIGH SENSITIVITY SPECTROMETER FOR ATMOSPHERIC MEASUREMENTS

THE ACCURATE MEASUREMENT OF CONCENTRATIONS OR FLUXES OF TRACE GASES IN THE ATMOSPHERE IS CRUCIAL TO MANY AREAS OF ATMOSPHERIC RESEARCH. INSTRUMENTATION BASED ON TUNABLE DIODE LASER ABSORPTION SPECTROSCOPY HAS WIDE GENERALITY FOR DETECTION OF MANY ATMOSPHERIC SPECIES. TO DATE, HOWEVER, SUCH SYSTEMS HAVE USUALLY BEEN BULKY AND AWKWARD TO OPERATE AND DO NOT HAVE ADEQUATE SENSITIVITY FOR THE MEASUREMENT OF A NUMBER OF IMPORTANT SPECIES THAT EXIST IN THE ATMOSPHERE AT LOW CONCENTRATIONS. SOUTHWEST SCIENCES, INC. PROPOSES TO DEVELOP A RAPID RESPONSE (FASTER THAN 0.1 SECOND) HIGH SENSITIVITY SENSOR USING SINGLE-MODE LIQUID NITROGEN-COOLED LEAD SALT DIODE LASERS. THE MAJOR OBJECTIVE OF THE PHASE I EFFORT IS TO USESUCH INSTRUMENTATION TO EXTEND THE SENSITIVITY OF DIODE LASER ABSORPTION MEASUREMENTS BEYOND PRESENTLY ATTAINED LEVELS. IN PARTICULAR, THE RESEARCHERS WILL STUDY AN IMPROVED MULTIPLE PASS CELL DESIGN COMBINED WITH HIGH FREQUENCY OPTICAL HETERODYNE TECHNIQUES THAT SHOULD PERMIT SHOT NOISE-LIMITED PERFORMANCE. RESULTS OF THE PHASE I STUDY WILL PROVIDE THE REQUIRED DESIGN INFORMATION FOR THE PHASE II DEVELOPMENT OF A HIGH SENSITIVITY, COMPACT INSTRUMENT WITH UNPRECEDENTED VERSATILITY FOR FIELD MEASUREMENT OF TRACE ATMOSPHERIC SPECIES.