DLS FAQ: Data Portability & Archiving

Apr 29, 2021
Applications: DLS
Instruments: BI-200SMNanoBrook SeriesParticle ExplorerParticle Solutions

In order for DLS data to be relatable to a physically meaningful parameter, frequently size, it is necessary to know a number of other parameters describing either the solvent, measurement conditions, or the configuration of a given hardware system. Brookhaven fully supports export of raw data, specially DLS autocorrelation functions, for fitting using more advanced algorithms. In addition to this, it is also possible to archive a DLS experiment in order to transfer it between workstations, or between different versions of our instrument control software. The archive files (.bak) allow for full data portability, and facilitate review of experimental data, as well as simplifying virtual instrument support.

DLS is a quick and effective way to measure the hydrodynamic size of a wide range of different nanomaterials. The DLS diameter is referred to by a variety of terms including the effective diameter, the hydrodynamic diameter, the z-average diameter, or the equivalent spherical diameter. Regardless of label, this diameter is calculated from a diffusion coefficient, which is the parameter that is determined during a DLS experiment. 

To make physical sense of a scattering experiment, raw data needs to be coupled with the relevant metadata (terms such as scattering angle, viscosity, solvent, temperature, laser wavelength and power). To this end a data archiving feature is available on all Brookhaven DLS acquisition software that bundles this information into a single portable data file format (.bak). This is in addition to supporting direct export of raw data which can be useful for analyzing correlation functions using third part curve fitting or analysis software. 

Particle Solutions archive file
Select either a single measurement or group of measurements in the Particle Solutions frontend to produce a single archive file that can be reloaded in any of Brookhaven’s DLS capable software packages.
Particle Solutions bak files
The .bak files produced by this archiving process will contain all relevant experimental metadata regardless of which platform generates them. Particle Explorer can Load Archive files produced by other Brookhaven DLS software.


  • DLS data is uninterpretable when decoupled from experimental metadata. 
  • Brookhaven’s instrument control software supports a fully portable, but proprietary, data archiving format that can be used to archive and reimport data produced across all of Brookhaven’s DLS products.
  • Data archiving and data export are separate processes, both of which are supported.

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