|Compact, Highly Sensitive Raman Spectroscopy System
Through the BMDO SBIR program, Process Instruments, Inc. (Salt Lake City, UT), has developed a compact, highly sensitive Raman spectroscopy system for commercial quality control and process monitoring applications. Using a high-power, frequency stabilized, near-infrared diode laser and very fast spectrograph, the system offers a portable and affordable way to analyze chemical concentrations of sample streams. Petrochemical, pharmaceutical, and polymer processing companies are currently evaluating system prototypes. Customers with ideas for new applications are actively being sought.
Through the BMDO SBIR program, Process Instruments, Inc., (Salt Lake City, UT), has developed a compact, highly sensitive Raman spectroscopy system. The key to this system is an external-cavity-stabilized, narrow linewidth, near infrared diode laser, which offers high power (up to 1.5 W) and long life (>9,000 hours). Other system components include a very fast (f/1.3) spectrograph, a thermoelectrically cooled charged-coupled device (CCD) camera, computer and interface electronics, a remote sample cell, and excitation and collection fibers.
System advantages include a simple, rugged, and compact design suitable for field use; low maintenance requirements due to the elimination of moving parts; and good spectrographic stability from a low-cost device. In addition, the proprietary external cavity design can be used with any existing high-power diode laser, which gives the system a large wavelength selection (640 nm to 1 micron) and therefore greater flexibility in detecting materials. Finally, the fiber-coupled input to the system can be multiplexed, which allows simultaneous monitoring of multiple samples and thus reduces the actual monitoring cost per site.
In the system, laser light is focused into an excitation fiber connected to a remote (up to several hundred meters away) Raman sample cell. Inside the cell, the light interacts with the sample to be characterized. Raman scattered light emanating from the sample is guided down one or more collection fibers to the Raman spectrometer. The spectrometer passes the optical signal through a filter, an optical slit, and a diffraction grating. The signal is then transmitted to the CCD, which converts the optical signal into an electronic one. The electronic signal is analyzed and converted by computer into a graphical representation of the chemical analysis of the sample stream.
Process Instruments developed the compact, highly sensitive Raman spectroscopy system under the BMDO SBIR program. Raman spectroscopy instruments could prove valuable for quality control and process monitoring during the manufacture of key components for terrestrial and space-based BMD systems.
In addition, Process Instruments has been awarded a 2001 BMDO SBIR Phase I contract to further develop its Raman spectroscopy system for testing the chemical state of new and aging rocket motors. Rapid, in-situ determination of solid rocket propellant chemistry could greatly reduce the need for destructive testing.
The system has been demonstrated to show the potential for generating relatively high laser powers suitable for commercial liquid- and solid-phase Raman spectroscopy applications. Short-term markets include petrochemicals, pharmaceuticals, polymer processing, food processing, semiconductor production, and environmental monitoring. Law enforcement (e.g. contraband and explosives detection) and medical diagnostics provide longer term markets for the Raman spectroscopy system.
Process Instruments has completed the majority of engineering tasks for its Raman spectroscopy system and is now heavily involved in applications development. To this end, the company has provided system prototypes to several large multinational corporations in the petrochemical (British Petroleum), pharmaceutical (Pharmacia), and polymer processing (Ato-Fina) industries. Interest in the technology has also been received from several firms researching portable glucose monitoring. Overseas inquiries are increasing, and Process Instruments recently formed an distributorship agreement with a company in Europe. The principal investigator is looking for customers with ideas for new applications.
In 1994, Dr. Lee Smith founded Process Instruments with the goal of moving Raman instrumentation out of the laboratory and into industry for process control applications. The company is focused on developing state-of-the-art, affordable, stable laser sources; matching, optically fast (f/1.3), efficient spectrographs; and integrated CCD detectors for use in liquid- and gas-phase industrial process Raman applications. It operates in nearly 4,000 ft2 of space, which includes a research and development area. The company has 8 employees, many of whom previously worked together under SBIR contracts to develop, manufacture, and market a medical Raman anesthesia and respiratory gas analyzer (the RascalTM) incorporating intracavity techniques.
Dr. Lee Smith
Process Instruments, Inc.
825 North 300 West Suite 225
Salt Lake City UT 84103-1414