NSF Award
9810572
9810572<br/>Benner<br/><br/> This Phase I Small Business Technology Transfer (STTR) project will demonstrate that a full-spectrum Raman analyzer prototype with no moving parts that incorporates a small, novel Raman optical-fiber based enhancement cell can rapidly measure Ethylene Oxide (EtO) and other gases down to low ppm levels. Raman's high degree of specificity minimizes signal cross-talk in complex multicomponent systems. The spectra have narrow peaks which can be observed easily even in the presence of moisture. In order to make gas-phase Raman analysis affordable and practical we will use an off-the- shelf laser diode array as a light source. A proprietary external-cavity configuration will narrow the linewidth to around 10 cm-1. A simple, fiber-optic loop will enhance the circulating laser energy by approximately 10 X to obtain sufficiently high laser energy for gas-phase detection at low concentrations. The Raman signal will be collected with a rugged, optically fast (f/1.4) volume- holographic spectrograph, and the full spectrum will be detected using a sensitive TE-cooled CCD array detector. This approach offers a simple, reliable instrument with no moving parts, for reduced maintenance and good stability. EtO is a colorless gas commonly used for sterilization of medical products that are temperature sensitive, which has been demonstrated to be a respiratory, skin, and eye irritant even at low concentrations (50 ppm). In addition, long-term exposure to EtO presents mutagenic, reproductive, and carcinogenic complications to humans. Below 700 ppm the odor of EtO cannot be detected. A gas sensor is needed to rapidly monitor EtO.<br/> The proposed work will demonstrate the ease of use and breadth of application of Raman instrumentation compared to conventional IR, mass spectroscopy, or GC methodologies in a large U.S. market for industrial process analyzers.
