High‐Energy Ion Beam Analysis

Abstract

Abstract It is very hard to identify the earliest application of high‐energy ion beam analysis (IBA), which was a natural outgrowth of accelerator‐based atomic and nuclear physics that started in the 1940s with the development of particle accelerators. In these early experiments, the composition of the target to be studied was well known, and it was the nuclear scattering or reaction cross‐section that was measured. It would not be surprising if one of the very first nuclear physics pioneers turned this emphasis around and used their beams to measure the compositional uniformity of an unknown sample. Perhaps the earliest known proposal for IBA was that of E. Rubin in 1949 at the Stanford Research Institute, which spelled out the principle of Rutherford backscattering spectrometry (RBS). Another very early application of IBA was performed by Harald Enge at MIT. Enge used mega‐electron‐volt deuterons from one of Van de Graaff's first accelerators with a magnetic spectrometer to measure the constituents of aluminized Formvar in perhaps the earliest materials analysis application of nuclear reaction analysis (NRA). It is interesting to note that the use of magnetic spectrometers to obtain ultrahigh depth resolution is now common. High‐Energy IBA is generally thought to apply when the ion beam has energy greater than 0.5 MeV. There are several attributes of high‐energy IBA, including (1) the ability to measure virtually any element in the periodic table, at times with isotopic specificity; (2) the ability to determine concentration as a function of depth; (3) that trace element sensitivity is not uncommon; and (4)that the technique is nondestructive with respect to the chemical makeup of the sample. The periodic table given provides a convenient overview of high‐energy IBA capabilities.