Prompt-gamma neutron activation analysis (PGNAA) is a technique used for determining the presence and amount of many elements simultaneously in samples ranging in size from small to very large.
In the coal and cement industries, there are many analytical techniques to detect and extract elements. One such technique is prompt-gamma neutron activation analysis (PGNAA)—a non-destructive method that continuously tests samples of varying sizes for the types and the quantity of elements present. As the technology measures the elemental composition of a test compound, it allows for real-time analysis of the materials in the ground. Before starting extraction operations, PGNAA can be used to detect the presence of gas, oil, sand, and shale deposits within a given site.
How Does Prompt Gamma Neutron Activation Analysis (PGNAA) Work?
The PGNAA process typically makes use of bulk material analyzers (see below image) to process samples. Among other components, the key features of this equipment include:
- A carrying/conveyor belt
- A strong neutron source (such as californium-252)
- A neutron source holder
- A control cabinet
Once the bulk analyzer belt carries the material within the enclosure component, the neutron source emits a beam of neutrons that penetrates the sample. The elements of the sample absorb these neutrons and emit prompt gamma rays which are captured by a sodium-iodized crystal and measured with a spectrometer. Each element emits a unique gamma ray. The energies of these gamma rays identify the neutron-capturing elements, and the intensities of the peaks at these energies reveal their concentrations. Customers use this information to analyze the composition and the quantities of elements such as sulfur, silicon, calcium, oxides, carbon, etc., which then are used to determine total moisture and a more accurate BTU.
The sample is continuously irradiated with a beam of neutrons from a californium-252 source. The elements of the sample absorb these neutrons and emit prompt gamma rays which are captured by a sodium-iodized crystal and measured with a spectrometer. Each element emits a unique gamma ray. The energies of these gamma rays identify the neutron-capturing elements, and the intensities of the peaks at these energies reveal their concentrations. Customers use this information to analyze the composition and the quantities of elements such as sulfur, silicon, calcium, oxides, carbon, etc., which then are used to determine total moisture and a more accurate BTU.
PGNAA applications include the analysis of coal, cement, and other minerals.
Why Is Californium-252 Used for PGNAA?
At the core of every PGNAA equipment is a strong neutron source. Californium-252 possesses several properties that make it well-suited for use in PGNAA:
- It is extremely radioactive and the only known isotope that spontaneously emits neutrons—one microgram releases 170 million neutrons every minute. This enables quick and easy on-site analysis of samples.
- It has a high melting point (~900° C), allowing for resistance in high-heat environments.
- Cf-252 sources can be tailored to fit the specifications of PGNAA equipment (depending on the source supplier). At FTC, for example, our sources are available in single-encapsulated and double-encapsulated capsule forms.
Advantages of Californium-252 and PGNAA in the Coal and Cement Industries
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The use of PGNAA powered by californium-252 in the coal and cement industries offer a number of advantages over alternative analysis techniques, such as:
- Analytical power. In addition to analyzing the composition and quantities of elements present in a sample, the method can also be used to determine total moisture and BTU.
- Real-time control. As PGNAA offers real-time analysis of samples, it allows for faster decisions about the viability of a site, as well as a much more streamlined method to acquire a comprehensive snapshot of sample contents—all of which contribute to greater cost savings.
- Reliable and consistent measurement and analysis. Compared to other methods, PGNAA offers the highest level of accuracy and responsiveness for elemental composition readings.
Californium-252 Sources for PGNAA at FTC
Coal and cement industry professionals often turn to californium-252 neutron sources for reliable and consistent analysis in PGNAA operations. For high quality and safe californium-252 sources, turn to FTC.
At Frontier Technology Corporation (FTC), we supply our NIST-certified californium-252 sources in both single- and double-encapsulated forms. We also produce extremely resilient Type-A containers that are DOT certified and follow the Code of Federal Regulations (CFR Title 49). These containers are designed to protect the element and the surrounding environment and personnel during storage, transport, and use. Once a source has been depleted, our customers are welcome to take advantage of our fee-free return program, and we will safely dispose of them.
For additional information about PGNAA and how we serve the coal and cement industries, contact us today.
Download Our Guide to PGNAA
Our guide offers a comprehensive overview of the PGNAA process, including what it is, how it works, what advantages it offers, how and where it is used, and the importance of Cf-252.
