The Stopping and Range of Ions in Matter

SRIM-2011

The accuracy of SRIM-2011 can be reviewed by viewing plots which compare existing Experiments and the equivalent SRIM calculations. In all of the below plots, there are two graphs shown for each example. The lower plot shows the ratio of Experiment /Theory for given ions and targets. The upper plot shows the same data which are normalized to the stopping of a typical ion/target combination. This allows one to view the same Experiment / Theory in a more natural plot. If this is confusing, you have to view a couple of plots to see what is meant. The plots have better resolution than shown in most browsers, which reduce the plot to fit your screen. Download or print the plot to see the full plot details.

There are 5 columns of plots. The first three columns are for the stopping of H, He and Li ions in any elemental target. If you want to see the experimental data available for the stopping of Li ions in Au targets, for example, go down the column under "Li Ions" until you find Au(79). This hyperlink will bring up the plot of Li in Au along with the data from 15 papers which have measured the stopping of Li in Au.

There is much less data for the stopping of heavy ions in elemental targets. These plots are divided into two columns. The first column allows you to pick any heavy ion, and the plot will show the accuracy of that ion into all solids. The individual targets are identified by using the chemical symbol as the plot-point. For example, if you select Oxygen Ions the plot will show these ions into all solids with experimental data from 66 papers. You will see separate plot points for stopping in Al, Ag and Au, for example. The second column is similar, except it shows the stopping of all heavy ions (atomic number > 3) in any elemental target. 

The plots below cover energies from 1 - 10,000 keV/amu (light ions) and 1 - 100,000 keV/amu for heavy ions. In order to understand the accuracy of high energy stopping powers, it is better to view them from the perspective of Bethe-Bloch theory and discuss the two major parameters of this approach: Shell Corrections and the target Mean Ionization Potential. This is discussed with an additional 92 plots on a separate page:  SRIM High Energy Plots

The stopping powers of SRIM has significantly improved from the last major updates in 1998. This improvement is almost entirely in the calculation of the stopping of  heavy ions since a totally new formalism is now used in SRIM. In 1998, the deviation of SRIM from more than 25,000 data points was 6.1%. For SRIM 2011, this error has been reduced to 4.6%. If you look at plots containing lots of data, for example He ions into Au (below), you can see that experimental scatter is about this level.

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Plots of SRIM-2011 Calculations and Experimental Results

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