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Unleashing the power of Prompt Gamma Neutron Activation Analysis (PGNAA) for industrial processing
PGNAA technology involves bombarding materials with neutrons and measuring the secondary or prompt gamma rays that are subsequently emitted. When a thermal, or relatively low energy neutron (<0.025 eV) closely approaches or collides with the nucleus of an atom there is a transfer of energy that triggers the sequence of events shown below.
The energy of the gamma-ray released as the nucleus returns to its stable state is associated with the atom from which it was released giving each element an identifying signature or fingerprint. Threshold of detection values for different elements are a function of their tendency to interact with neutrons and determine the suitability of PGNAA for alternative applications. That said, the applicability of PGNAA methods extends right across the processing industries as the following resources illustrate.
Useful resources
See here for several pieces of information that can help, please visit the resources section to find more in depth information.
Neutron supply
There are two main options for neutron supply for PGNAA technology. One is a radioisotope, Californium 252 (252Cf), and the other is a neutron generator system. Such systems deploy PFTNA, using isotopes of hydrogen, deuterium (2H) and tritium (3H,) to produce neutrons via a fusion reaction. One distinctive difference when using a neutron generator versus a traditional Cf-252 source is therefore the ability to turn off the neutron generator when not in use.
System design
In addition to the neutron source, the performance and ease of use of PGNAA online analyzers is defined by detector quality and configuration and the extent to which system hardware and software support integration within the process.
Scintillation detectors with a high purity crystalline structure are the technology of choice for gamma-ray detection. These produce photons, proportional in energy to the energy of the detected gamma-rays, that are amplified and converted into electrical signals to generate a composite energy spectrum for the sample as shown below.
When it comes to system configuration, cross-belt analyzers such as the Thermo Scientific CB Omni Agile, and Thermo Scientific ECA-3 Elemental Cross-belt Analyzer are installed directly on the conveyor belt to provide minute-by-minute, uniform measurement of the entire material stream. This approach eliminates sampling errors and delivers data at a high frequency thereby helping to minimize variability in material quality. The Thermo Scientific CQM Flex Coal Analyzer is designed to fit in line with a mechanical sampling system to offer higher precision and accuracy. PGNAA technology is equally suitable for slurries, with systems such as the Thermo Scientific GS Omni Analyzer enabling the measurement of multiple process streams depending on measurement frequency requirements.
Data presentation and use
The high measurement frequency of online PGNAA systems makes effective data handling and presentation an essential element of any project. Optimizing data use is the key to achieving a good rate of return on any investment in PGNAA technology and powerful, industry-relevant software can be critical in this regard.
For Research Use Only. Not for use in diagnostic procedures.