skip to main content NIST Center for Neutron Research NIST Center for Neutron Research National Institute of Standards and Technology
Home Live Data Instruments CHRNS Proposals

Compute Neutron Attenuation and Activation

This form estimates the neutron scattering and absorption cross sections for a given sample composition. Note that the calculation can significantly underestimate absorption due to resonance effects, but resonant neutron absorption rarely occurs in powder diffraction measurements.

The form also estimates the expected levels of neutron activation for typical neutron flux used at the NIST BT-1 Neutron Diffractometer assuming a 24 hour irradiation. (This computation only performed when all elements are isotopically at their natural abundance).

This form is offered for estimation purposes. The NCNR does not keep records of samples evaluated with this form.

Note that use of this form is not a substitute for consulting with a Health Physicist. All samples must be cleared by a NIST Health Physicist before removal from the NCNR.

Enter the chemical formula, by entering a chemical symbol and a number of formula units (e.g. H 2 O 1 for H2O). For a specific isotope, enter the mass number before the chemical symbol (e.g. 7Li for 7Li).

Element Formula Units

Wavelength: Å.
Packed* Density: g/cc
(*This is the density adjusted for
voids due to packing, often ~0.6
times the crystallographic density)

Last modified 27-October-2005 by website owner: NCNR (attn: Craig Brown)