In static SIMS, dedicated to the analysis of the top monolayer, the primary ion dose is kept below 1E12 ions/cm² and the mass spectrum reveals MOLECULAR information. In dynamic SIMS mode, the primary ion dose is not limited and exceeds 1E12 ions/cm². In this mode, ELEMENTAL and ISOTOPIC information can be obtained from the mass spectrum. It allows surface, "bulk" and 2D/3D analyses.
The ionization yield of most elements varies by decades, depending on the chemical environment. This property is used in SIMS instruments to increase the sensitivity of the technique: a dynamic SIMS instrument must be equipped with Oxygen and Cesium primary ion beams in order to enhance, respectively, positive and negative secondary ion intensity by 2 to 3 orders of magnitude compared to the use of noble gas ions. Oxygen gas can also be flooded onto the surface to oxidize it and increase positive ion emission.
When sending keV ions onto a solid surface, (at least !) three phenomena occur simultaneously: 
- the sputtering of (mainly) the top monolayer atoms, induced by the collision cascade,
- the ionization of a small fraction of the secondary particles,
- the primary ion implantation in the solid (and associated change of composition, surface work function, etc...). 
Starting from the surface (or going through an interface), the concentration of the implanted primary species (oxygen or cesium) will vary, then reach an equilibrium (after a few nm, depending on the conditions). As soon as this is achieved, reliable quantification is possible with reference standard samples, using Relative Sensitivity Factors.

One of the main application of dynamic SIMS is the analysis of trace element depth distribution (for example, dopant in semiconductors). Impact ion energy is adjusted depending on the applications. Low energy (down to 200-300 eV) is used to reduce atomic mixing due to the collision cascade and improve depth resolution to the nanometer level. High energy (up to 20-30 keV) is chosen to go deeper (10-20 microns), faster (µm per min), and improve detection limits and image resolution.
The CAMECA SIMS are optimized for dynamic SIMS analysis.