Photon detectors in atomic spectrometry

Many elemental analysis methods are based on the use of atomic line spectra. These include atomic emission spectrometry, with flame, arc, spark and glow discharge as possible radiation sources, and plasmas, in particular Inductively Coupled Plasmas or ICP, and laser-produced plasmas or LIBS (Laser-Induced Breakdown Spectrometry); atomic absorption spectrometry, with flame and furnace as atomization sources; and atomic fluorescence spectrometry. Atomic line spectra are linked to the production or absorption of photons. Photons can be easily transported over long distances, and collected using very simple optics, mirrors or lenses. Photons have no mass, which means they will not produce memory effects or implantation phenomena, for example at the detector. To be able to identify the lines emitted and measure their intensity, it is necessary to be able to quantify the number of photons involved. The role of the detector is to transform the photons into a signal, generally an electrical signal, which can then be amplified, processed and used in system software. This article describes the various photon detectors currently used in analytical atomic spectrometry.