STOPPING POWER OF CARBON FOR HEAVY-IONS UPTO COPPER

Stopping powers for ions of O, Cl, Sc, Ti, Cr, Mn, Fe and Cu in the en ergy range 0.2-1.0 MeV/n have been measured in carbon foils using the elastic recoil ion technique and a twin detector system. Very heavy io ns of Gold and Iodine of energy around 100 MeV have been employed to g enerate the various recoil ions using pure thin (approximate to 1000 A ngstrom) elemental/compound targets. The data have an overall average accuracy of 6%. The stopping power for Sc, Mn and Fe ions in the energ y region 0.2-1.0 MeV/n as well as those for Ti and Cu ions in the ener gy region below 0.45 MeV/n are perhaps the first such measurements. Th e limitations of LSS theory even within the range of its applicability has been demonstrated. Varelas and Biersack estimates agree well in t he region of their applicability lying above the ion velocity limit se t for LSS theory. Northcliffe and Schilling predictions as well as the TRIM estimates provide the best fit with data. However, one does noti ce variations upto 25% for some ions at lower energies in the case of later estimates. Northcliffe and Schilling estimates lie within 10% of the experimental values for all the ions studied except for 0 and Cu ions at certain energies only.