Energy loss straggling in thick mylar polymeric foils for swift heavy ions in fractional energy loss limits ΔE/E ∼ 5-80%

The energy loss straggling in thick mylar (monomer composition: C10H8O4) polymeric foils has been measured for swift heavy ions covering Z = 3-22, in the fractional energy loss limits ΔE/E ∼ 5-80%. These measured straggling values have been compared with the most commonly used Bethe-Livingston collisional straggling formulation after modifying it suitably for thick targets. Further, the charge-exchange straggling values have been extracted from the measured values and were found to be consistently higher than the corresponding values deduced from Yang's et al. formulation. Finally, an analytical expression has been developed for charge-exchange straggling for ion-polymer combinations, considered in the present study.