Activation analysis refers to nuclear analytical techniques that utilize radiation to identify and quantify elements in a given sample. The equipment used in activation analysis enables detection of elements down to parts-per-billion levels, making it a highly sensitive analytical method.
Radioisotope Sources
At the core of any activation analysis setup is the radioisotope source used to irradiate samples. Common radioisotope sources include cobalt-60, americium-241, and calcium-45. These radioisotope sources produce high-energy photons like gamma rays that interact with atomic nuclei in the sample, transforming stable isotopes into radioactive ones. Different radioisotope sources are chosen based on the types of elements needed to be analyzed and the required penetration depth. For instance, higher energy gamma rays from cobalt-60 allow analysis of thicker samples.
Sample Irradiation and Radioactive Decay
Following exposure to gamma rays from the radioisotope source, the activated samples are removed to an area where they can decay radioactively in a radiation-shielded chamber. During this decay period, characteristic gamma rays are emitted by the newly formed radioactive isotopes. Detection of these low-intensity gamma rays using specialized equipment allows identification of elements present in the original sample. The decay period needed ranges from minutes to days depending on the half-lives of radioactive isotopes formed.
Gamma-Ray Spectrometers
The backbone of any Activation Analysis Equipment setup is the gamma-ray spectrometer, which acts as the detector to analyze the decay radiation from activated samples. Contemporary gamma spectrometers mostly use high-purity germanium (HPGe) detectors, which offer high resolution and sensitivity for low-energy gamma rays. HPGe detectors coupled to multi-channel pulse-height analyzers facilitate the identification of individual gamma photon energies, allowing accurate elemental analysis. Windowless geometries further improve efficiency.
Automated Systems
Modern activation analysis equipment features highly automated systems to maximize throughput and reproducibility. Pneumatic sample changers rapidly shuffle samples in and out of the irradiation chamber, with computer control of irradiation times. Computerized sample identification and logging integrated with gamma spectrometer data systems automate acquisition and analysis. Touchscreen interfaces provide easy setup and operation. Robotic sample handlers are also used in high-throughput applications like process monitoring or mineral exploration to optimize workflow.
Applications
Activation analysis finds diverse applications owing to its low detection limits and non-destructive nature. It is commonly employed in trace elemental analysis of materials in industries such as metallurgy, petrochemicals, semiconductors and electronics. In the medical field, it is applied to investigate mineral balances and diagnose nutritional deficiencies. Archaeology and paleontology utilize it for dating artifacts and fossils. Environmental monitoring studies employ activation analysis to detect pollutants in air, water and soil. Adaptations to field portable equipment have expanded its use to in-situ analysis in applications such as mineral exploration.
Activation analysis is an extremely sensitive technique for determining trace elemental composition. Continuous advancements in radioisotope sources, detectors, automation, and data systems have significantly improved the capabilities, scope, and efficiency of activation analysis equipment. The availability of high-performance yet user-friendly systems has increased applications across diverse domains. Activation analysis promises to remain an invaluable analytical tool, complementing other techniques in addressing emerging needs of science.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it