Introduction Laser diffraction is a widely used technique for measuring the size distribution of particles in a sample. Known for its speed, accuracy, and versatility, it has become a fundamental tool in industries such as pharmaceuticals, environmental science, and chemistry. In this post, we explore the principles of laser diffraction, its applications, the types of instruments used, and its historical evolution to give you a deeper understanding of how laser diffraction supports modern particle characterization.
What is Laser Diffraction? At its core, laser diffraction involves passing a laser beam through a dispersed sample of particles. As the particles interact with the laser, they scatter light at various angles. The angle and intensity of the scattered light are measured by detectors, and this information is used to calculate the particle size distribution. Because laser diffraction can be used for both wet and dry samples, it is an incredibly versatile technique for a range of industries.
How Does Laser Diffraction Work?
Wet Dispersion: For wet dispersion, a liquid (referred to as a dispersant) is chosen to suspend the particles. This dispersant must be a liquid in which the particles are insoluble, such as water or alcohol. The dispersant is circulated through the instrument via a flow system that passes through a transparent cell, typically a small circular window. The sample is introduced into the circulating liquid, and as the particles flow past the laser, the light is scattered. Detectors capture the scattered light, and the diffraction pattern is analyzed to calculate the particle size distribution.
Dry Dispersion: Dry dispersion works a bit differently. Here, the sample is placed in a funnel and guided down a vibrating trough, which feeds it into a stream of compressed air. The air blast disperses the particles, propelling them through a transparent window where they interact with the laser beam. The diffraction patterns are recorded, and the instrument calculates the particle size distribution. This method is especially useful for materials that may dissolve in liquids or for situations where maintaining a dry state is critical.
Applications of Laser Diffraction Laser diffraction plays a crucial role in numerous industries and applications. Here are some of its most notable uses:
Why Choose Laser Diffraction? Laser diffraction offers several advantages over traditional particle sizing techniques such as sieving, sedimentation, and optical microscopy. Key benefits include:
Laser diffraction is a powerful and versatile tool for particle size analysis. Its ability to analyze wet and dry samples quickly and accurately has made it an essential technique across industries like pharmaceuticals, environmental science, and materials development.
At RJ Lee Group, we employ the latest laser diffraction instrumentation to analyze wet and dry samples. Whether developing new materials, ensuring product quality, or conducting environmental research, laser diffraction is an indispensable part of the process, especially when backed by our extensive industry experience and scientific expertise.
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