Description

The Brookhaven Instruments Approach to Light Scattering

Light Scattering occurs when polarizable particles in a sample are bathed in the oscillating electric field of a beam of light. The varying field induces oscillating dipoles in the particles and these radiate light in all directions. This important and universal phenomena is the basis for explaining why the sky is blue, why fog and emulsions are opaque and other observations. It has been utilized in many areas of science to determine particle size, molecular weight, shape, diffusion coefficients etc. Brookhaven Instruments’ scientists have extensive experience in the development of instruments and methods for light scattering and this experience has been incorporated into the BI-200SM to make it the finest instrument available for research applications of light scattering.

With a Brookhaven Instruments BI-200SM Research Goniometer System, this rich field of exploration is open to you for studies of both Static Light Scattering (SLS) and Dynamic Light Scattering (DLS).

The Bl-200SM Research Goniometer System provides access to all of these studies with an automatic, modular, and versatile system. It is a precision instrument designed for exacting scattering measurements. Based on a special turntable with precision ball bearings and stepping motor, the Bl-200SM’s modern design and quality construction guarantee precise measurements due to the wobble-free movement of the detector. It is field proven in hundreds of laboratories. It is ideal for macro-molecular studies and submicron particle sizing.

By taking advantage of the multiple inputs available on the TurboCorr correlator a new capability of the BI-200SM system is created. By adding an optical signal splitter to the beam of scattered light and a second detector it is possible to eliminate the effects of very high speed interference from the detector(s). This Cross Correlation System provides remarkably clean information as seen in the article we have presented.

The BI-200SM’s modularity simplifies system expansion. Featuring a standard optical rail, the BI-200SM can be used with neutral density filters, a polarizer, an analyzer, and a reference detector. Special sample requirements can often be met by changing the cell holder design or size.

Features at a glance

• Stepping motor controlled, multiangle measurements
• Particle size and size distributions
• M_w, R_g, A₂ for dilute polymer solutions
• Cross-correlation detector option
• Avalanche photodiode detector option
• CONTIN, Zimm, Guinier, Fractal, and more

Advantages of the BI-200SM Research Goniometer System

• Both DLS and SLS modes: Correlation & Intensity Measurements
• Large angular Range: 8° to 155° with 25mm cells: 15° to 155° with 12 mm cells.
• Fine Adjustment Control: Read angle to 0.01° directly on large, fine-control adjustment knob.
• Open Design/Standard Optical Rails: Facilitates user customizations for special purposes.
• Temperature Control: Heating and cooling via any standard external circulator Separate temperature and filtration plumbing.
• Special Design Glass Vats: Specially polished and flat entrance window ensures minimum flare.
• Alignment Cell: Fine-screw vertical adjustment makes finding the center of rotation easier.
• Multiple Laser Line Filters: Filter wheel with 632.8 (HeNe), 514.5/488.0 nm (Ar+), one open position for weak scatterers, and 2 blank (shutter) positions. Also available with 532 nm bandpass filter
• Enhanced Viewing Optics: Coated, precision achromats coupled with behind-the-slit viewing and high-quality eyepiece make alignment easier.
• Additional Alignment Aperture: Alignment of laser much simpler and faster.
• Variety of Cell Holders: High precision cell holders standard, low-priced round cells available: 27.5 mm dilution vials fit cell holder sleeve. Special small-volume cell available.