Malvern Panalytical Inc.

Malvern Instruments Limited

Jason Corbett

Alex Malm

Fraser McNeil-Watson

David Stringfellow

Robert Jack

Nigel Lightfoot

Rhys Poolman

Richard Scullion

Douglas Hamilton

A method of characterising particles in a sample, comprising: obtaining a scattering measurement comprising a time series of measurements of scattered light from a detector, the scattered light produced by the interaction of an illuminating light beam with the sample; producing a corrected scattering measurement, comprising compensating for scattering contributions from contaminants by reducing a scattering intensity in at least some time periods of the scattering measurement; determining a particle characteristic from the corrected scattering measurement.

Particle characterization

Particle characterisation

An apparatus for particle characterisation, comprising: a sample cell for holding a sample; a light source configured to illuminate the sample with an illuminating beam and a plurality of light detectors, each light detector configured to receive scattered light resulting from the interaction between the illuminating beam and the sample along a respective detector path, wherein each respective detector path is at substantially the same angle to the illuminating beam.

A method of determining particle size distribution from multi-angle dynamic light scattering data, comprising: obtaining a series of measured correlation functions g(&#x3b8;) at scattering angles &#x3b8;; and solving an equation comprising wherein: K(&#x3b8;) is the instrument scattering matrix computed for angle i, x is the particle size distribution, and &#x3b1;is the scaling coefficient for angle i. The method comprises using the steps: a) providing initial estimates for scaling factors &#x3b1;to &#x3b1;, and defining &#x3b1;=1; b) iterating scaling factors &#x3b1;to &#x3b1;using a non-linear solver; c) solving for x using a linear solver; d) calculate residual; e) repeat steps b) to d) while the residual is greater than a predefined exit tolerance.

Multi-angle dynamic light scattering

Disclosed herein is a method of characterizing particles in a sample. The method comprises illuminating the sample in a sample cell with a light beam, so as to produce scattered light by the interaction of the light beam with the sample; obtaining a time series of measurements of the scattered light from a single detector; determining, from the time series of measurements from the single detector, which measurements were taken at times when a large particle was contributing to the scattered light; determining a particle size distribution, including correcting for light scattered by the large particle.

A particle-sizing instrument is provided, comprising: a sample cell for receiving a sample comprising a plurality of particles; a light source configured to illuminate the sample with a light beam to produce scattered light by the interaction of the light beam with the particles; a first optical system comprising a first and second optical element respectively configured to split a portion of the scattered light into a first and second portion of scattered light: a second optical system configured to receive the first and second portion of scattered light from the first optical system, and to recombine the first and second portion of scattered light to produce an interference signal at a detection location, and a detector configured to detect the interference signal at the detection location.

Particle sizing by optical diffraction

A particle characterisation instrument, comprising a light source, a sample cell, an optical element between the light source and sample cell and a detector. The optical element is configured to modify light from the light source to create a modified beam, the modified beam: a) interfering with itself to create an effective beam in the sample cell along an illumination axis and b) diverging in the far field to produce a dark region along the illumination axis that is substantially not illuminated at a distance from the sample cell. The detector is at the distance from the sample cell, and is configured to detect light scattered from the effective beam by a sample in the sample cell, the detector positioned to detect forward or back scattered light along a scattering axis that is at an angle of 0&#xb0; to 10&#xb0; from the illumination axis.

Particle characterisation instrument

The invention relates to methods and apparatus for determining properties of a surface. Embodiments disclosed include an apparatus for measuring a surface charge of a sample, comprising: a sample holder having an opposed pair of electrodes and configured to hold a sample in position in a measurement volume between the electrodes such that a planar surface of the sample is aligned orthogonal to the electrode surfaces; a measurement chamber for containing a measurement liquid and having an open end configured to receive the sample holder to position the electrodes in a preset orientation; a laser light source positioned and configured to direct a laser beam through the measurement chamber between the electrodes and parallel to the planar surface of the sample when the sample holder is received in the measurement chamber; and a detector positioned and configured to detect scattered light from the measurement volume, wherein the apparatus is configured to allow for detection of the scattered light by the detector over a range of distances from the surface of the sample.

Surface charge measurement

A cuvette carrier comprising: a plurality of walls defining a holding volume for a cuvette; a first and second transmissive region included in the plurality of walls; and a first optical polariser arranged to polarise light passing through the first transmissive region.

Cuvette carrier

A cuvette carrier comprising: a plurality of walls defining a holding volume for a cuvette; a first and second transmissive region included in the plurality of walls; and a first optical polarizer arranged to polarize light passing through the first transmissive region.

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Malvern, United Kingdom

Jason Corbett