NCNR tools on the web

This page has links to pages with older versions of the applets for older browsers. Some of the functions of the newer applets will not work here, but most should work fine.

Calculate scattering length densities (SLD's)

Given a chemical compound and a mass density in g/cm³ this applet can calculate the real and imaginary portions of the scattering length density of the material for neutrons and x-rays. It can also calculate the macroscopic incoherent scattering and absorption cross sections and the penetration depth for neutrons. It uses the data shown in the online table of neutron scattering lengths and cross sections.

Plan a SANS experiment at NCNR

This applet contains information about the configurations of the three SANS instruments available for users at the NCNR. It is meant to assist users in determining the instrument configuration which optimizes the instrument to collect data on the desired features in the sample.

Calculate SANS data on the web.

If you are using a browser that can run Java 1.0.2 code you can calculate SANS data using any of 20 different particle models. You can also smear the SANS data using a set of instrument parameters which you can vary to simulate experimental conditions.

Documentation and usage instructions for the SANS calculator is currently available for the following particle models:

• Form Factors
  • Sphere
  • PolyHardSphere
  • PolyRectSphere
  • CoreShell
  • PolyCoreShell
  • PolyCoreShellRatio
  • Cylinder
  • HollowCylinder
  • CoreShellCylinder
  • Ellipsoid
  • OblateCoreShell
  • ProlateCoreShell
  • TwoHomopolymerRPA
  • DAB
  • TeubnerStrey
  • Lorentz
  • PeakLorentz
  • PeakGauss
  • PowerLaw
  • BE_RPA
• Structure Factors
  • SquareWell
  • HardSphere

More documentation is on the way.

You can view the Java source files for the models here. Just click on the .java files to see the source.

Calculate neutron reflectivities on the web.

Make a model profile with layers, define the fronting and backing media and calculate neutron reflectivities. The ability to smear these reflectivities to different types of resolution will come as soon as I can come up with a less computationally intensive way of calculating it.

Convert between volume and mass fractions.

This is a simple calculation, but it is an easy one in which to make a mistake. When a mistake destroys your only sample, it can really ruin your day. If you know the mass densities of the two things you are mixing and either the volume or the mass fraction you desire you can use this tool to calculate the other.

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For more information or to make suggestions contact Alan Munter
Last modified 15-April-2002 by website owner: NCNR (attn: Alan Munter)