Nephelometer
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorHermann E. Gerber
Life of this patent
Estimating the term…
Abstract
A nephelometer and method for measuring optical quality of a marine atmosphere and particularly characterizing its aerosol particle size distribution, visual range and aerosol optical effects in the visible and infrared. There is provided a housing for entrapping a momentary aerosol sampling, a laser source for providing a narrow collimated beam of radiant energy (usually light) through the sample, and plural spaced-apart cosine sensors facing across the radiant energy illuminated sample, with one reading a slightly greater angle than the other, for receiving aerosol particle scattered light. Integrated outputs from the sensors when compared with laser output intensity as a reference signal provide an indication of aerosol particle size distribution and concentration.
Claims5
A nephelometer for monitoring optical quality of a marine atmosphere comprising:
- a housing including an elongate chamber for containing a sampling of marine atmosphere including aerosol particles;
- a laser providing pulses of collimated electromagnetic radiation through the sampling longitudinally of the elongate chamber;
- plural cosine sensors in the chamber longitudinally spaced along the radiated sampling and looking generally transverse to the elongate chamber;
- means admitting scattered radiation to one of the sensors over an angular range from about 170.degree. downstream to about 13.degree. upstream of the radiation, and to the other sensor over an angular range from about 170.degree. downstream to about 3.degree. upstream of the radiation whereby said other sensor receives more forward radiation than the one;
- a third sensor receiving radiation from the laser through the sampling for monitoring laser output intensity and producing a reference signal in response thereto;
- said pair of sensors providing respective output signals in relation to the intensity of scattered radiation received by each over its entire angular ranges;
- and,
- means comparing the sensor output signals and reference signal;
- thereby providing scattered radiation information.
Dependencies are inferred from the claim text.