SINGLE-PARTICLE CONTAMINANT SIZING SPECTOMETER FOR SPACE APPLICATION

A NOVEL DEVICE IS PROPOSED FOR DETECTING AND SIZING INDIVIDUAL PARTICLES COMPRISING THE SPACECRAFT CONTAMINANT ENVIRONMENT, (EITHER WITHIN ENCLOSURES OR EXTERNAL). THE OPERATING PRINCIPLE OF THE DEVICE IS BASED UPON THE WELL-KNOWN PHENOMENON OF FORWARD SCATTERING TO DEDUCE PARTICLE SIZE. THE MAIN ADVANTAGES OF THE DEVICE ARE: 1. A RELATIVELY LARGE VOLUME IS SAMPLED (A MINIMUM OF 1/2 LITER) WITHOUT DISTURBING THE FLOW FIELD ENVIRONMENT, 2. THE SENSING REGION IS REMOTE, BEING SITUATED ALONG THE OPTICAL AXIS OF THE DETECTING MODULE AND EXTENDING FROM A MINIMUM DISTANCE TO A MAXIMUM DISTANCE, BOTH OF WHICH PARAMETERS CAN BE TAILORED TO MEET THE SPECIFIC REQUIREMENTS OF A GIVEN EXPERIMENTAL OR OTHER USE CONFIGURATION, 3. THE SIZING RANGE CAN BE MADE TO EXTEND FROM THE SUBMICRON REGIME TO BEYOND 100 M, BY SIMPLY SELECTING THE APPROPRIATE OPERATING WAVELENGTH (OR SET OF WAVELENGTHS). 4. THE SIZING ACCURACY IS NOT STRONGLY DEPENDENT UPON KNOWLEDGE OF THE REFRACTIVE INDEX OF THE PARTICLE, AND 5. THE RAW OUTPUT DATA ARE PRODUCED IN A FORM THAT IS CONVERTED INTO PARTICLE SIZE WITHOUT THE NEED FOR EXCESSIVELY COMPLICATED DATA PROCESSING ALGORITHMS.