Allscan - Model PGNAA - Online Elemental Analyzers
From Elemental Analyzers
The AllScan PGNAA analyser combines state-of-the-art nuclear technology with ground-breaking spectra modelling and powerful statistical analysis. Installed on a conveyor belt, the AllScan delivers accurate, minute-by-minute elemental analysis and reporting of the chemical composition of bulk materials and key process parameters.
At the heart of the AllScan is PGNAA – prompt gamma neutron activation analysis. Material on the conveyor is bombarded with neutrons emitted from radioactive isotope.
When neutrons collide with an element in the material, gamma rays are emitted with a specific energy unique to that element – in effect, creating chemical signature for that element. The greater the amount of an element in the material the greater the number of gamma rays emitted with the corresponding specific energy. By measuring the specific energy of the gamma rays that are emitted and the counts of gamma rays, an accurate analysis of the chemistry of the material is generated on a second by second basis.
RTI has taken this tried and proven technology and made it better – much more accurate, easy to install, calibrate, set up and maintain. In partiuclar, the AllScan incorporates a unique analytical calculation concept called Dura-G™.
Dura-G Improves the Performance of Standard PGNAA
A well-known challenge with the PGNAA technology is a highly complex raw spectrum comprising of all the individual elemental spectra plus significant “noise/disturbance factors” from sample presentation,material depth variations, hydrogen signal etc. All of these factors make up the “presentation effects” and can often be stronger than the “composition effects”. Dura-G™ is a unique modelling and calculation concept based on sophisticated algorithms that separate the effect of environment, belt load and profile variations on the measured spectra from the effect of elemental variations.
Thus, by smart removal of “noise components” from the complex raw Prompt Gamma spectrum, Dura-G creates a cleaned-up
- considers all the spectral components independently and ensures these components are correctly allocated to the separate Composition and Material Presentation effects
- increases the signal to noise ratio of the measured compositional signal and improves the deconvolution of same to provide output data with reduced measurement error compared to the
- traditional raw spectrum
- supports a sophisticated sample free calibration methodology to provide an elemental analyser that is not dependant on material or ongoing calibration techniques
The Dura-G technology smartly separates the composition and presentation effects, i.e. it allows for all of the spectral components of the complex Prompt Gamma spectrum to be correctly allocated to Composition or Presentation effects. In the processing, the significant noise attributable to hydrogen is also eliminated. The below illustration outlines how the unique AllScan concept differs from the conventional calculation concept used by other players in the market:
AllScan also includes a powerful algorithm – DuraSum™ – that eliminates the need for time-based averaging of data in order to obtain stable results. This means that changes in elemental composition of the material are reported almost instantaneously, rather than many minutes later. This in turn allows for rapid operational control.