View source for Dynamic Light Scattering

===== BI-200SM Laser Light Scattering Goniometer =====
[http://www.brookhaven.co.uk/products/zeta-potential/light-scattering/bi-200sm.html BI-200SM]
 
Modular systems for static and dynamic light scattering

The BI-200SM Goniometer with precise stepper motor control of detector angle is the centre piece of Brookhaven's modular research light scattering system. Designed primarily for use with the BI-9000AT Correlator, it meets the most exacting requirements for both static (SLS) and [[Dynamic  Light Scattering]] (DLS) applications in polymer and particle characterization.

The turntable is mounted on a large (200mm) diameter precision bearing, essential to eliminate detector arm wobble and ensure accuracy throughout an angular range of 80 - 1550.


[[Image:Bi-200sm.jpg‎]]
A choice of three detectors is offered – two types of photomultiplier and an avalanche photodiode (APD); the latter offers improved sensitivity, mainly to longer wavelengths e.g. the red of a He-Ne laser. A second detector can be mounted at a fixed angle of 900 if required. Mounts can be tailored to suit virtually any type of laser, the most popular being solid state DPSS (usually 532nm) or tuneable argon ion devices.

A variety of glass or quartz cells can be accommodated within the sample holder which is surrounded by refractive index matching fluid contained in the ultra-high quality, temperature controlled vat. Purity of the fluid is ensured by the recirculating filtration system. A similar accessory is available for filtering the sample solution / suspension, especially for SLS applications or when working with very small particles in DLS.

The BI-200SM has been designed for ease of use and, for an instrument of this kind, offers unmatched ease of alignment and maintenance. Brookhaven’s BI-IST Alignment Software aids this process, providing easy, automatic testing procedures which can be used as a routine check on performance or following maintenance operations.

Applications of BI-200SM based light scattering systems are many and varied. They include submicron particle size distribution analysis of colloids, micelles, emulsions etc., study of nucleation, crystallisation and aggregation processes, determination of molecular weight, radius of gyration and second virial coefficient of polymers in solution.

For SLS applications in which the specific refractive index increment as a function of polymer concentration (dn/dc) is required, the Brookhaven BI-DNDC is the ideal complement to a BI-200SM system. Software for light scattering applications is listed under the BI-9000AT Correlator section.

==== BI-200SM Special Features: ====

* Designed for DLS and SLS: 	polymer and particle characterisation.
* Large Angular Range: 	80 to 1550 with 25mm cells: 150 to 1550 with 12mm cells.
* Fine Adjustment Control: 	Read angle directly to 0.010.
* Open Design/Standard Optical Rails: 	Facilitates user customisation.
* Temperature Control: 	Heating and cooling via external circulator. Separate temperature and filtration paths.
* Precision Glass Index Matching Vat: 	Specially polished and flat entrance window ensures minimum flare
* Alignment Cell: 	Facilitates alignment with centre of rotation.
* Multiple Laser Line Filters: 	Filter wheel with standard laser wavelength filters plus one open and 2 closed (shutter) positions.
* Enhanced Viewing Optics and Alignment Aperture: 	For easier alignment.
* Variety of Cell Holders: 	High precision cell holders. For cells, see below.

==== Options and Accessories: ====

* BI-DNDC: 	Differential Refractometer.
* BI-HV: 	High voltage PMT power supply.
* BI-LRM: 	Laser rail and mounts. Available for most lasers.
* BI-TCD: 	External circulator for temperature control with digital setting and readout..
* BI-FC: 	Filtration/circulation system for index matching liquid.
* BI-RC12: 	12mm o.d. round glass cell
* BI-SCG: 	10mm path length glass square cell & cap.
* BI-RC25: 	25mm o.d. round quartz (Burchard type) cell, dual Teflon tops, mounting ring.
* BI-RC27: 	27.5mm o.d. sample cell, package of 100 with screw caps. Routine DLS use
* BI-SVC: 	Small-volume cell for precious samples.
* BI-2DS: 	Diode reference detector including mount.
* BI-PA: 	Polarisation Analyser. Glan-Thompson prism, 5x10-6 extinction, 2-position mount.
* BI-APD: 	Avalanche Photodiode detector option. Higher sensitivity, mainly to longer wavelengths cf PMT
* BI-SFS: 	Sample Filtration System. Highly recommended when working with small particles or polymer solutions.