Particle-Induced X-ray Emission (PIXE)

Introduction to Particle-Induced X-ray Emission (PIXE)

Several types of excitation beams generate X-rays with energy typical of the target elements. Photon excitation (by X-rays) produces X-ray fluorescence spectroscopy. Electron excitation in a scanning electron microscope or an electron microprobe produces energy- or wavelength-dispersive X-ray spectroscopy (depending on the X-ray dispersion and detection method). PIXE is a powerful but non-destructive elemental analysis technique that is now frequently used by geologists, archaeologists, art conservators, and others to assist answer issues about provenance, date, and authenticity. MaTestLab is one of the leading testing service providers in the USA and Canada. We have a large network of testing laboratories in the USA.

Principle and Methodology of PIXE

PIXE is a technique that identifies elements in a sample using charged particles. When high-energy particles strike atoms, they create vacancies that emit energy in the form of X-rays. The energies of such X-rays are characteristic of the element from which they originated. The steps or processes involved are sample preparation, radiation, X-ray detection, and data analysis. This will involve cleaning the sample from contaminations, then bombarding it with a finely focused beam of high-energy particles. These X-rays are then detected by the silicon drift detector, which determines their energy and intensity.

Instrumentation

For PIXE, a particle accelerator produces a proton beam with a few MeV in energy. The beamline focuses the beam through the apparatus onto the sample with the aid of some focusing elements, like magnetic lenses. The sample is housed within the sample chamber in a vacuum or controlled atmosphere to minimize interference. High-resolution X-ray detectors capture the emitted X-rays for accurate elemental analysis of the material under test. The data acquisition system digitizes the analog signals and analyzes data for the sample’s elemental makeup.

Applications of PIXE

PIXE is a nondestructive method used in archaeology and art conservation to analyze the elemental composition of geological samples, archeological specimens, thin films, and proteins. It is also used in protein analysis to determine the elemental composition of liquid and crystalline proteins, making it a popular choice for dating objects.