Apparatus and method for analyzing particles

Patent metadata

Field	Value
Publication number	US-10852248-B2
Application number	US-201916523226-A
Country	US
Kind code	B2
Filing date	Jul 26, 2019
Priority date	Jul 27, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

One aspect is an apparatus for analyzing particles a capillary as a measuring cell with a hollow channel for receiving or passing through a test sample containing the particles includes a light source for generating a light beam, an optical device for coupling the light beam into the hollow channel at an input point for the purpose of illuminating the test sample, and a detector for detecting scattered light exiting the hollow channel. In one aspects, the hollow channel has an internal diameter D H in the range of 10 μm to 60 μm, that the light beam has a radial light intensity distribution with a minimum beam diameter D L , wherein the following applies to the diameter ratio D L /D H : 0.05<D L /D H <2.00, and that the light beam has an angle of incidence of less than 2 degrees in relation to the hollow channel's longitudinal axis on entering the hollow channel.

First claim

The invention claimed is:

1. An apparatus for analyzing particles, comprising:
a glass capillary as a measuring cell with a hollow channel for receiving or for passing through a test sample containing the particles, said hollow channel having a hollow-channel longitudinal axis and a hollow-channel internal wall;
a light source for generating a light beam and an optical device for coupling the light beam into the hollow channel at an input point for the purpose of illuminating the test sample; and
a detector for detecting scattered light exiting the hollow channel;
wherein the hollow channel has an internal diameter DH in the range of 10 μm to 60 μm;
wherein the light beam has a radial light intensity distribution with a minimum beam diameter D L , wherein the following applies to the diameter ratio D L /D H : 0.05<D L /D H <2.00; and
wherein the light beam has an angle of incidence (Ψ) of less than 2 degrees in relation to the hollow channel's longitudinal axis on entering the hollow channel.

2. The apparatus according to claim 1 , wherein the glass capillary is straight at least along a signal-detecting length.

3. The apparatus according to claim 1 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 100 μm, and a wall thickness of no more than 10 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

4. The apparatus according to claim 1 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 500 μm and a wall thickness of no more than 5 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

5. The apparatus according to claim 1 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 1000 μm, and a wall thickness of no more than 2 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

6. The apparatus according to claim 1 , wherein the glass capillary consists of quartz glass.

7. The apparatus according to claim 1 , wherein the optical device is configured as an optical fiber in the form of a multi-mode optical fiber or as a single-mode optical fiber with a fiber core and a cladding surrounding the fiber core, and wherein the optical fiber has a numerical aperture NA to which the following applies: NA<0.05.

8. The apparatus according to claim 7 , wherein the capillary is formed in a plate-like body with mutually opposing flat sides, wherein the flat sides of the body form external walls of the capillary.

9. The apparatus according to claim 1 , wherein the hollow channel has an internal cross-section with at least one flattened portion and/or in that the capillary has an external cross-section with at least one flattened portion.

10. The apparatus according to claim 1 , wherein the detector is configured such that scattered light is detectable along a signal-detecting length of up to 20 cm.

11. The apparatus according to claim 1 , wherein the hollow-channel wall has an internal surface with a surface roughness that is defined by an average roughness depth R a of less than 1 nm.

12. A method for analyzing particles, comprising:
providing a measuring cell in the form of a glass capillary with a hollow channel having a hollow-channel longitudinal axis and a hollow-channel wall;
introducing a test sample containing the particles into the hollow channel, wherein the test sample has a refractive index Δn M ;
generating a light beam using a light source;
coupling the light beam into the hollow channel by means of an optical input device at an input point for the purpose of illuminating the test sample; and
detecting scattered light exiting the hollow channel using a detector;
wherein a glass capillary is used in which the hollow channel has an internal diameter D H in the range of 10 μm to 60 μm;
wherein the light beam has a radial light intensity distribution with a minimum beam diameter D L , wherein the following applies to the diameter ratio D L /D H : 0.05<D L /D H <2.0; and
wherein the light beam has an angle of incidence (Ψ) of less than 2 degrees in relation to the hollow channel's longitudinal axis on entering the hollow channel.

13. The method according to claim 12 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 100 μm, and a wall thickness of no more than 10 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

14. The method according to claim 12 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 500 μm, and a wall thickness of no more than 5 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

15. The method according to claim 12 , wherein the glass capillary has a hollow-channel wall with a wall thickness of at least 1000 μm, and a wall thickness of no more than 2 mm, and in that the hollow-channel wall viewed in the radial direction has a homogeneous refractive index profile.

16. The method according to claim 12 , wherein a glass capillary composed of quartz glass is used.

17. The method according to claim 12 , wherein as the optical device an optical fiber in the form of a multi-mode optical fiber or a single-mode optical fiber with a fiber core and a cladding surrounding the fiber core is used, and wherein the optical fiber has a numerical aperture NA to which the following applies: NA<0.05.

18. The method according to claim 12 , wherein the test sample has a refractive index Δn M and that the glass of the capillary has a refractive index Δn K , wherein the following applies: Δn M <Δn K , preferably Δn M <Δn K −0.1.

Assignees

• Heraeus Quarzglas

Inventors

• Weidlich Stefan
• Schmidt Markus

Classifications

• G01N15/0205 Primary

  by optical means · CPC title

• G01N15/14

  Optical investigation techniques, e.g. flow cytometry · CPC title

• G01N2015/0294

  Particle shape · CPC title

• G01N2015/1493

  Particle size · CPC title

• G01N2015/1497

  Particle shape · CPC title