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SRIM is a group of programs which calculate the stopping and range of ions (up to 2 GeV/amu) into matter using a quantum mechanical treatment of ion-atom collisions (assuming a moving atom as an "ion", and all target atoms as "atoms"). This calculation is made very efficient by the use of statistical algorithms which allow the ion to make jumps between calculated collisions and then averaging the collision results over the intervening gap. During the collisions, the ion and atom have a screened Coulomb collision, including exchange and correlation interactions between the overlapping electron shells. The ion has long range interactions creating electron excitations and plasmons within the target. These are described by including a description of the target's collective electronic structure and interatomic bond structure when the calculation is setup (tables of nominal values are supplied). The charge state of the ion within the target is described using the concept of effective charge, which includes a velocity dependent charge state and long range screening due to the collective electron sea of the target.
A full description of the calculation is found in our tutorial book "SRIM - The Stopping and Range of Ions in Solids", by J. F. Ziegler and J. P. Biersack in 1985 (a new edition was published in 2009). This book presents the physics of ion penetration into solids in a simple tutorial manner, then presents the source code for SRIM programs with a full explanation of the physics. Further chapters document the accuracy of SRIM and show various applications. Available on this website are plots showing SRIM stopping powers and all available experimental data for H and He ions into all targets.
TRIM (the Transport of Ions in Matter) is the most comprehensive program included. TRIM will accept complex targets made of compound materials with up to eight layers, each of different materials. It will calculate both the final 3D distribution of the ions and also all kinetic phenomena associated with the ion's energy loss: target damage, sputtering, ionization, and phonon production. All target atom cascades in the target are followed in detail. The programs are made so they can be interrupted at any time, and then resumed later. Plots of the calculation may be saved, and displayed when needed (it takes 5 seconds to begin viewing a saved calculation).
SRIM results from the original work by J. P. Biersack on range algorithms (see J. P. Biersack and L. Haggmark, Nucl. Instr. and Meth., vol. 174, 257, 1980) and the work by J. F. Ziegler on stopping theory (see "The Stopping and Range of Ions in Matter", volumes 2 - 6, Pergamon Press, 1977-1985). The various versions of SRIM are described briefly in the file VERSION on the SRIM package.
The SRIM program originated in 1983 as a DOS based program and was converted to Windows in 1989.
If you use SRIM programs in a scientific publication, please mail a copy to the authors. This will help continued support of SRIM in the future.
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