Abstract: A computerized system for in situ deep level characterization during irradiation in semiconductors has been set up and tested in the beam line for materials science studies of the 15 MV Pelletron accelerator at the Inter-University Accelerator Centre, New Delhi. This is a new facility for in situ irradiation-induced deep level studies, available in the beam line of an accelerator laboratory. It is based on the well-known deep level transient spectroscopy (DLTS) technique. High versatility for data manipulation is achieved through multifunction data acquisition card and LABVIEW. In situ DLTS studies of deep levels produced by impact of 100 MeV Si ions on Au/n-Si(100) Schottky barrier diode are presented to illustrate performance of the automated DLTS facility in the beam line. ©2008 American Institute of Physics

Abstract: The projectile charge-state dependence of methane fragmentation is studied at a constant projectile (Arq+, 1q7) velocity of 0.42 a.u. using the technique of time-of-flight mass spectroscopy. The relative cross sections for fragment production are reported as a function of the incident projectile charge state. The fragments appearing as molecular ions show a decrease in cross sections with increasing projectile charge state as opposed to the carbon ions which show an increase with increasing projectile charge state.

Abstract: We report on the results of dissociation dynamics of multiple charged acetylene molecules formed in collision with 1.2 MeV Ar8+ projectiles. Using the coincidence map, we can separate out the different dissociation pathways between carbon and hydrogen ionic fragments as well as complete two-body breakup events. From the measured slopes of the coincidence islands for carbon atomic fragments and theoretical values determined from the charge and momentum distribution of the correlated particles, we observe a diatomlike behavior of the C–C charged complex during dissociation of multiply charged C2H2. We conclude that this behavior in breakup dynamics is a signature of sequentiality in dissociation of this multiply charged molecular species. The shape and orientation of the islands give further information about the momentum balance in the fragmentation process of two- or many-body dissociation pathways. Kinetic energy release of different breakup channels are reported here and compared with values calculated from the pure Coulomb explosion model.