Heavy ion energy loss straggling data from Time of Flight stopping force measurements

The accuracy of heavy ion beam analytical techniques such as Heavy Ion-Elastic Recoil Detection Analysis (HI-ERDA) depends on, among other factors, the accuracy of basic ion beam data such as stopping force and energy loss straggling, used as input in ion beam analysis programs. The adaptation of the Time of Flight (ToF) ERDA technique for stopping force measurements in free standing target foils brings with it the possibility of extracting energy loss straggling information from the ToF derived energy spectra. In essence several straggling values can be obtained over a continuous energy range from a single measurement. A presentation is made here of an exploration of that possibility using the passage of 12C, 16O, 27Al and 84Kr ions in the oxide ceramic ZrO2 as examples. The experimental straggling values, obtained over the 0.1–0.6 MeV/u energy range, are normalised to Bohr straggling and compared with Yang’s empirical formulation, which is widely used in ion beam analysis programs.