Carbon cluster studies using the NSC Pelletron

The cesium sputter negative ion source of the NSC 16 MV Pelletron accelerator has been used to produce a variety of cluster negative ions. One of the various studies that has been carried out is the comparison of the negative cluster ion intensity distribution obtained by sputtering two different samples of carbon, viz, graphite and amorphous carbon. The Cn− ion intensity distribution as a function of the cluster mass shows some remarkable differences as well as some similarities in the two cases. Most of the observations could be interpreted using existing theoretical models. However, a number of observations such as the intensity distribution of the CsCn− ions, which is totally different for the two samples, are still not understood. Some of these clusters have been accelerated to MeV energies using the Pelletron accelerator. A calculation of the repulsive Coulomb energies has been performed for charged clusters of various sizes and compared with theoretically calculated values of average binding energies. The highest possible charge states that can be expected of some of these clusters have been predicted and compared with experimental measurements.