Browse Prior Art Database

Airborne Microorganism Detection

IP.com Disclosure Number: IPCOM000091465D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Townsend, VT: AUTHOR

Abstract

This system for detecting microorganisms in the atmosphere is sensitive and fast, and also provides ranging information. When microorganisms are irradiated with ultraviolet light, they undergo a fluorescence at a wavelength 400-500 Angstroms larger than their excitation. Because of atmospheric absorption, excitation in the range 2500-2700 Angstroms is preferred. A 10-20 nanosecond pulse is generated by Q-switched laser 1(Nd/3+/) at 10,600 Angstroms, and is twice doubled in frequency in KDP crystals 2 and 3 to produce a pulse at 2650 Angstroms. This pulse is reflected from dichroic mirror-filter 4 into lens 5 and lens 6. It illuminates the micro-organisms 7, and a return pulse at 3150 Angstrom results. This return pulse passes thru filter-mirror 4 and is focused by lens 8 onto detector 9.

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Airborne Microorganism Detection

This system for detecting microorganisms in the atmosphere is sensitive and fast, and also provides ranging information. When microorganisms are irradiated with ultraviolet light, they undergo a fluorescence at a wavelength 400-500 Angstroms larger than their excitation. Because of atmospheric absorption, excitation in the range 2500-2700 Angstroms is preferred. A 10-20 nanosecond pulse is generated by Q-switched laser 1(Nd/3+/) at 10,600 Angstroms, and is twice doubled in frequency in KDP crystals 2 and 3 to produce a pulse at 2650 Angstroms. This pulse is reflected from dichroic mirror-filter 4 into lens 5 and lens 6. It illuminates the micro-organisms 7, and a return pulse at 3150 Angstrom results. This return pulse passes thru filter-mirror 4 and is focused by lens 8 onto detector 9. The detected pulse is amplified and shaped by circuitry 10 and is applied to counter 11 to stop a count previously initiated by optical leakage of the transmitted pulse at 2650 Angstroms. Target range is displayed directly by counter 11.

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