VRF Visual RobFit
y-Spectrometry Analysis Software

Application for
nuclear spectral analysis

  • This application for analysis of high-resolution
    gamma-ray spectra has been developed using non-linear fitting techniques to fit full-spectrum nuclide shapes.

  • In contrast to conventional methods based on the results of an initial peak-search, the VRF
    analysis method forms a spectrum-wide shape for each nuclide as well as user-enabled parameters of energy calibration, attenuation or self-absorbing materials and coincidence summing until no better fit to the data can be

  • This approach allows identification of minor peaks that are masked by larger, overlapping peaks that would not otherwise be possible.

In research, radiation protection and industry

  • Universities, research centers, nuclear medicine

  • Industry- and nuclear technology

  • Dismantling, consulting, waste management

  • Environmental, health and food surveillance and laboratories

  • Civil defense, emergency response, border, safety, security and access control

A new powerful method of high-resolution gamma-ray spectral analysis:

  • A spectrum-wide shape is formed for each nuclide with activity adjusted at each iteration

  • For all nuclides the full-spectrum shapes are summed and automatically repeated for best fit

  • VRF is visually-driven for reporting, graphing and specialized analysis

  • Detector energy, resolution and efficiency calibrations best fitting by up to 6-order Pàde

  • High sensitive identification of minor peaks that are masked by larger overlapping peaks

  • Automatic activity correction for decay during acquisition & collection and since collection

  • Automatic random & true-coincidence summing and single, double and x-ray escape corrections

  • Three different attenuation groups are selectable including low-energy peak-tail fitting

  • Applicable to activation analysis for prompt and delayed neutrons

  • Implemented calculation of isotopic ratios, e.g. for U-235/U238 or Pu-240/Pu-239

  • Editable libraries (txt-files) for 1180 isotopes (3840 in preparation), selectable decay sequences (chains), all x-rays, 183 neutron activated nuclides and customizable groups of isotopes

The percentage by weight reference for depleted uranium

is U235/U238=0.200

Example: Isotopic ratios

Isotopics is the estimate of the percentage by weight or percentage by atom of a selected isotope to the sum of all isotopes of a selected element. Two important measurements of isotopics are the percentage by weight of U-235 in uranium, and the percentage by weight of Pu-240 in plutonium.

VRF offers a simple way to estimate isotopics for cases in which the element is almost entirely composed of two isotopes, using the Isotopics tab page shown here for depleted uranium.


- Non linear -
Least-Squares Fitting Techniques
for Gamma Spectrometry"

"After 40 years γ-spectrometry"

Finally a complete analysis of high resolution HPGe spectra

The latest generation in γ-spectra analysis