The atom probe is a microscope with resolution capabilities of viewing and analyzing atomic-sized objects. Specifically, an atom probe is used in the field of materials science, a discipline that applies the various properties of matter to other sciences and the engineering industry. The device enables scientists to investigate molecular structure at the atomic level and determine the macroscopic properties of the materials. Applied physics, chemistry, nanoscience and forensic engineering all utilize the instrument to identify characteristics of necessary components to research.
One of the important facets of the atomic probe microscope is its use of time-in-flight spectroscopy technology. This technique measures the time frame in which it takes an atom or other objects to travel through a certain medium. It can also be used with various energy events such as electromagnetic waves. The purpose is to determine the velocity or length of the path and determine the flow rate of a particle or other phenomena. Basically, an electrical field is used to accelerate the ions in a medium, which can measure kinetic energy and is used to find the velocity.
Field ion microscopy is also used in the atom probe as a technique for analysis. This identifies the image and composition of atoms within the surface of the sharp metal tip of an object. The radius must be less than 50 nanometers and placed within a vacuum chamber with extremely low pressures. An imaging gas like helium or neon is introduced, while cryogenic temperatures are established. After an electrical field is initiated, the ions become positively charged and magnify the composition of the tip.
One of the most advanced forms of this technology is atom probe tomography. A position-sensitive detector is used in the process to generate three-dimensional images. This improvement to the technique, using laser pulses, can be utilized to view the components of other materials besides metals. Certain semiconductor materials such as silicon or other insulating materials can be analyzed using this method of atom probe technology.
The atom probe was primarily designed by German physicist Erwin Wilhelm Muller in 1967. Additional scientists, such as J.A. Panitz and S. Brooks McLane expanded on the concept at the time. However, it wasn't until the commercialization of the laser pulsed atom probe in 2005 that the technology became highly prevalent in the fields of materials science.