EP0182618A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Sample cell for light scattering measurements
Assignee: Wyatt Technology LLC
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Filing: 1985-11-14
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Granted: —
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Expires: 2005-11-14
Abstract
Abstract A sample cell (3) of light transmissive material is described that permits the measurement of the light scattering properties of very small liquid-borne samples with negligible background interference from the illumination source. A technique is described whereby the cell construction permits the measurement of the illumination intensity at the scattering sample itself, permitting, thereby, the normalization of each detected scattered signal. The cell structure and detection method incorporated therein also permit measurement of extremely small angle scattered intensities without interference of the incident light beam itself. For this purpose the cell contains a channel (41 for the sample and a light beam (1) is passed in the length direction of the channel, detector means (2) being arranged to detect light scattered from the sample and passed through the light transmissive material.
Inventors
- 👤 Jeff M. Reece
- 👤 Steve Phillips
- 👤 Philip J. Wyatt
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:05
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/01; G01N21/03; G01N21/17; G01N21/47; G01N21/49; G01N21/51; G01N2021/4704; G01N2021/4711; G01N2021/513
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
122 words
An apparatus for use in measuring light scattering properties of particles in a liquid suspension illuminated by a collimated light beam, the apparatus being characterised by: a cell (3) formed of light transmissive material and defining a channel (4) for the liquid suspension; liquid suspension inlet and outlet means (7) for permitting liquid suspension to be supplied to and removed from said channel (4); and light inlet and outlet means (6,6') for allowing passage of a collimated light beam through the channel (4) in the direction along its length, whereby, in use with a liquid suspension in said channel, light scattered by said suspension will pass through said light transmissive material so that it can be detected by suitably arranged detectors (2).
Claim 2
Independent Claim
122 words
An apparatus for use in measuring light scattering properties of particles in a liquid suspension illuminated by a collimated light beam, the apparatus being characterised by: a cell (3) formed of light transmissive material and defining a channel (4) for the liquid suspension; liquid suspension inlet and outlet means (7) for permitting liquid suspension to be supplied to and removed from said channel (4); and light inlet and outlet means (6,6') for allowing passage of a collimated light beam through the channel (4) in the direction along its length, whereby, in use with a liquid suspension in said channel, light scattered by said suspension will pass through said light transmissive material so that it can be detected by suitably arranged detectors (2).
Claim 3
Dependent Claim
42 words
An apparatus according to Claim 1 wherein the light inlet and outlet means (6,6') are spaced from the middle of the channel (4) by a distance at least eight times the maximum cross-sectional dimensional of a major portion of the channel (4).
Claim 4
Dependent Claim
58 words
An apparatus as claimed in Claim 1 or 2 and in which the cell (3) has an optically polished outer surface and is so constructed that a cross section of the cell taken through the channel (4) has a substantially circular form and the channel (4) extends chordwise of that cross section, having an optically polished internal surface.
Claim 5
Dependent Claim
16 words
An apparatus as claimed in Claim 3 in which the cell (3) is of cylindrical form.
Claim 6
Dependent Claim
16 words
An apparatus as claimed in Claim 3 in which the cell (3) is of spherical form.
Claim 7
Dependent Claim
26 words
An apparatus as claimed in Claim 5 in which the cell has been formed by joining two optically polished hemispheres with a refractive index matching adhesive.
Claim 8
Independent Claim
35 words
An apparatus as claimed in any preceding claim in which the light and liquid inlet and outlet means are provided by components (5) connected respectively to an inlet and an outlet of the channel (4).
Claim 9
Dependent Claim
88 words
An apparatus as claimed in Claim 7 in which the components each define a duct for liquid suspension, each duct having a first branch (9) in line and communicating with said channel (4) and having a light transmissive region (6,6') forming a light inlet or outlet as the case may be, there being a second duct in the component angled with respect to and communicating with said first duct (9) whereby liquid suspension can be supplied to or removed from the first duct (9) via the second duct.
Claim 10
Independent Claim
34 words
An apparatus as claimed in any preceding claim which includes a laser arranged to supply the collimated light beam of a form with a maximum cross-sectional dimension less than that of the channel (4).
Claim 11
Dependent Claim
37 words
An apparatus as claimed in Claim 9, wherein the laser is such that the maximum cross-sectional dimension of the light beam in the channel (4) is less than half the minimum cross-sectional dimension of the channel (4).
Claim 12
Independent Claim
67 words
A method of measuring light scattered by particles suspended in a liquid, characterised by the steps of: placing the particle-carrying liquid at an optically polished surface of light transmissive material; illuminating the liquid with a collimated light beam passing parallel to the surface; and detecting light which has been scattered by particles in the liquid to pass through said polished surface and a portion of said material.
Claim 13
Independent Claim
67 words
A method of measuring light scattered by particles suspended in a liquid, characterised by the steps of: placing the particle-carrying liquid at an optically polished surface of light transmissive material; illuminating the liquid with a collimated light beam passing parallel to the surface; and detecting light which has been scattered by particles in the liquid to pass through said polished surface and a portion of said material.
Claim 14
Dependent Claim
21 words
A method according to Claim 11 wherein the material has a refractive index which is greater than that of said liquid.
Claim 15
Dependent Claim
23 words
A method according to Claim 11 or 12 wherein the particle-carrying liquid is placed in a straight channel (4) extending through said material.
Claim 16
Dependent Claim
36 words
A method according to Claim 13 wherein the collimated light beam is produced by a laser and has a maximum cross-sectional dimension in the channel which is less than the minimum cross-sectional dimension of said channel.
Claim 17
Dependent Claim
34 words
A method according to Claim 11, 12, 13 or 14 wherein the material is in the form of a cylinder and the particle-carrying liquid is placed in a channel extending chordwise through the cylinder.
Claim 18
Dependent Claim
35 words
A method according to Claim 11, 12, 13 or 14 wherein the material is in the form of a sphere and a particle-carrying liquid is placed in a channel which extends diametrically of the sphere.
Claim 19
Independent Claim
76 words
A method as claimed in any one of Claims 11 to 16, wherein the scattered intensities of light are normalized by: A. measuring the intensity (I ) of light after it has passed through the sample along the beam paths; B. measuring a fraction (If) of the incident light source intensity before the light enters the sample; and C. dividing all measured scattered intensities at various scattering angles by the quantity (√I f I s ).
Claim 20
Dependent Claim
76 words
A method for correcting for refraction effects of apparatus as claimed in in Claim 1, the method being characterised by the step of determining a required set of scattering angles at which scattering is to be detected, and the step of placing detector means (2), for detecting light passing through the cell having been scattered by liquid suspension, at transformed angular positions such that said transformed positions correspond respectively to the required set of scattering angles.
Claim 21
Dependent Claim
65 words
A method according to Claim 18 wherein the detector means (2) are disposed around the cell (3) when in the form of a cylindrical scattering cell and the transformed angular positions 0' are derived from the scattering angles 0 by the relation where n 1 is the refractive index of the scattering medium and n 2 is the refractive index of the cylindrical scattering cell.
Claim 22
Dependent Claim
74 words
A method according to Claim 18 wherein the detector means (2) are disposed around the scattering cell of spherical form in sets lying along great circles, and the detector angular positions, θ', referred to the polar axis through the liquid suspension, are derived from the scattering angles 9 by the relation where n 1 is the refractive index of the scattering medium and n 2 is the refractive index of the spherical scattering cell.
Claim 23
Dependent Claim
30 words
A method according to Claim 18, 19 or 20, in which the detector means are all arranged to detect light scattered from substantially the same point in the liquid suspension.
Claim 24
Independent Claim
75 words
A method for normalizing the scattered intensities of light scattered by a sample of a suspension illuminated by a collimated light beam, the method comprising: A. measuring the intensities of light after it has passed through the sample along the beam path; B. measuring a fraction (I ) of the incident light source intensity before the light enters the sample; and C. dividing all subsequently measured scattered intensities at various scattering angles by the quantity
Claim 25
Independent Claim
75 words
A method for normalizing the scattered intensities of light scattered by a sample of a suspension illuminated by a collimated light beam, the method comprising: A. measuring the intensities of light after it has passed through the sample along the beam path; B. measuring a fraction (I ) of the incident light source intensity before the light enters the sample; and C. dividing all subsequently measured scattered intensities at various scattering angles by the quantity
References Cited (Backward Citations)
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