Particle Velocity and Energy

The mean particle velocity for most metal atoms having an atomic number larger than 20 is between 4 and 8x105 cm s 1, if sputtering is performed with krypton ions of 1200 eV. 

When using argon ions, the velocities are between about 3x and 6x10s cm s 1 and are little influenced by changes in the ion energy between 600 and 1200 eV. 

Heavy elements have the highest particle energy (e.g. U, E 44 eV) and light elements the highest particle velocity (e.g. Be, v = 1 lxl0Tcm s 1). 

The energy increases linearly with mass. For the lighter elements, it is about 10 eV and on average achieves 30 to 40 eV in the case of the heavy elements. Materials with a high sputtering yield usually have low particle energy. 

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