NCNR tools on the web

Calculate sample activation and scattering cross sections in neutron beam New calculator!

Calculates neutron activation (and optionally neutron scattering) given the neutron cross sections for most abundant elements and their isotopes. Much more flexible than the older Java calculator.

Calculate scattering length densities (SLD's) (old Java calculator)

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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Report errors or make inquiries to Alan Munter, <alan.munter@nist.gov>

Last modified 14-November-2013 by website owner: NCNR (attn: Bill Kamitakahara)