Method for determining in situ the absorption coefficient of particulate media using pulsed laser technique

• US 4,475,816 A
• Filed: 02/15/1980
• Issued: 10/09/1984
• Est. Priority Date: 02/15/1980
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Mooradian, Gregory C., Stotts, Larry B.
• Primary Examiner(s): ROSENBERGER, RICHARD A
• Application Number:
  US06/121,937
• Time in Patent Office: 1,698 Days
• Field of Search: 356/337, 356/338, 356/341, 356/432, 356/433, 356/434, 356/436, 356/437, 356/438, 356/441, 356/442
• US Class Current: 356/437
• CPC Class Codes: G01N 21/534 by measuring transmission alone, i.e. determining opacity

Abstract

A true indication of a fluid'"'"'s absorption coefficient takes into effect the contributing factors of absorption and particle multiple scattering. A pulsed optical source transmits radiation through a relatively large volume of a certain particulate fluid medium. A detector or irradiance meter is gated so as to provide waveforms on a monitor which are characteristic of the absorption and multiple scattering of the medium. Using the transmittance and multiple line spread of the received signal a nearly real-time in situ analysis can be performed to provide scientists, communications specialists, etc. with the capability to anticipate operational parameters.

Claims

1. A method for determining in situ the true absorption coefficient of a particulate media comprising:

pulsing a beam of optical radiation through a wide path in the particulate medium;

locating a radiation detector to receive the radiation at the end of the wide path;

actuating the detector for predetermined intervals to pass signals each representative of both the absorption and particulate multiple scattering of the particulate media as the beam passes therethrough; and

monitoring the magnitudes of the representative signals by comparing the representative signals to known values to determine the absorption coefficient.

2. A method for determining in situ the true absorption coefficient of a particulate media comprising:

pulsing a beam of optical radiation through a wide path in the particulate medium, the step of pulsing includes the diffusing of the beam for radiation through the particulate media;

locating a radiation detector to receive the radiation at the end of the wide path;

actuating the detector for predetermined intervals to pass signals each representative of both the absorption and particulate multiple scattering of the particulate media as the beam passes therethrough; and

monitoring the magnitudes of the representative signals by comparing the representative signals to known values to determine the absorption coefficient.