If you are interested in learning how NAA works, click here.  This page is for providing sensitivities, costs, and sample preparation procedures for those interested in having samples analyzed at the UWNR using NAA.

Neutron Activation Analysis is a physical method of analysis of materials for elemental composition.  A sample is exposed to neutrons, resulting in activation of many of the constituent elements.  Specific radiations emitted by the activation products are detected to determine the amount of the elements present in the sample.  At the UWNR, we practice Instrumental Neutron Activation Analysis (INAA), a technique in which gamma ray emissions are detected.  Beta and positron emitters may also be detected to determine elements, but this requires radiochemical procedures to separate elements.  Gamma ray emissions are usually distinctive enough that elements may be determined without chemical separations or special sample preparation.

Neutron activation analysis is capable of simultaneous determination of many elements in most samples even when parameters are selected to optimize detection sensitivity of one particular element.  Information on additional elements is obtained with no additional effort or expense.

A table is available that gives some indication of the range of sensitivities for different elements.  Please note that the sensitivities given can be considerably enhanced for most materials.  The document on costs indicates the groups of elements that can usually be simultaneously determined.

Samples of relatively uniform volume and mass are sealed inside polyethylene vials.  Standards (materials with known elemental composition) are similarly prepared.  An irradiation time is selected, depending upon elements to be detected.  Likewise, decay time (from end of irradiation to start of counting) and counting time are selected for the particular analysis desired.  Standards and samples are counted on high purity germanium gamma ray spectrometers.  The analysis program can calculate results based on element nuclear characteristics, but standardization is preferred.

Results are returned to the experimenter as files, on disk or via email, in a format for printing or a format for direct import into spreadsheets or databases.  In addition, graphical representation of the data can be made available.  Click here to see available output formats.  Paper copies of the results are also supplied if requested.

We specialize in analysis of large groups of samples with similar composition, since our counting and analysis is highly automated.  The method gives good sensitivity for many elements, and requires little sample preparation other than that needed to provide a sample typical of the material that can fit into the standard vials used - see the document on sample preparation.

We can generally predict (based on previous analyses) whether or not a particular element can be measured in a specific concentration in a particular matrix.

 

Last Modified: 9/5/2007