REAL-TIME HYDRAZINE MONITORING WITH SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS)

LARGE QUANTITIES OF HYDRAZINE AND NITROGEN TETRAOXIDE ARE USED IN THE SPACE SHUTTLE OPERATIONS. LEAKS OF THESE MATERIALS CAN PRESENT SIGNIFICANT HAZARDS TO THE SAFETY OF THE GROUND AND FLIGHT CREW AND THE SPACE SHUTTLE ITSELF. IN ADDITION, THE TOXIC NATURE OF THESE MATERIALS REQUIRES THAT THEIR CONCENTRATIONS IN THE ENVIRONMENT BE MONITORED ATTHE PARTS-PER-BILLION LEVEL. THE GOAL OF THE PROPOSED WORK IS THE DEVELOPMENT OF A SENSITIVE, "REAL-TIME" SENSOR FOR HYPERGOLIC GASES BASED ON SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS). THE SERS SIGNAL, WHICH CORRESPONDS TO THE VIBRATIONAL SPECTRUM OF A MOLECULE ADSORBED ONTO SPECIFIC METAL OR METAL OXIDE SUBSTRATES, IS OBTAINED FROM THE RAMAN SCATTERING OFF THE SUBSTRATE USING A VISIBLE LASER SOURCE. THE SERS TECHNIQUE CAN BE USED FOR THE QUALITATIVE AND QUANTITATIVE ANALYSIS OF NUMEROUS COMPONENTSIN BOTH GASEOUS AND LIQUID ENVIRONMENTS. THE GOAL OF THE PHASE I PROGRAM IS TO DEMONSTRATE THE FEASIBILITY OF DEVELOPING A RELIABLE SENSOR BASED ON SERS FOR THE "REAL-TIME" DETECTION OF HYDRAZINE AND MONOMETHYLHYDRAZINE. THE DESIGN AND TESTING OF ACTUAL INSTRUMENTS WILL BE UNDERTAKEN IN PHASE II.