Abstract
In a tandem accelerator the knowledge of distribution of charge states as well as the overall transmission of incident ions is of great importance for optimized use of the accelerator. We have studied the effect of the stripper gas pressure on the charge state distribution and the transmission of incident carbon ions ($^{12}\mathrm{C}^{1\ensuremath{-}}$) stripped in ${\mathrm{N}}_{2}$ gas target in a tandem accelerator in the energy range of 0.2--1.7 MeV. The observed charge state fractions of the outgoing beam show transition from nonequilibrium to equilibrium distribution as the stripper gas pressure is varied. The experimentally measured average charge values at different stripper gas pressures are compared with an empirical model for the equilibrium average charge. Apart from the charge state distribution, the stripper gas pressure is found to have a more interesting effect in the transmission of incident carbon ions ($^{12}\mathrm{C}^{1\ensuremath{-}}$), which displays a maximum with pressure in the nonequilibrium region. The observed transmission behavior is explained qualitatively.
Highlights
Low energy tandem accelerators are used for extraction and acceleration of various ion species for material science research
The ion beam which enters the high energy acceleration column after passing through the stripper medium consists of different charge states and these are accelerated to different energies while emerging out of the high energy end of the acceleration column
We have summarized experimental results of the effect of stripper gas pressure on average charge, charge state fractions (Fq), and transmission (N) of incident 12C1À ions stripped in N2 in a tandem accelerator in the energy range 0.2–1.7 MeV
Summary
Low energy tandem accelerators are used for extraction and acceleration of various ion species for material science research. In a tandem accelerator the negatively charged ions are extracted from the source and accelerated to high velocity by the large positive potential at the terminal. The high velocity negative ion beam passes through the stripper medium present at the center of the acceleration tube. In the stripper medium the negative ions lose some electrons and become positive. These positive ions are further accelerated by the difference between positive potential at the terminal and the ground potential at the end of the high energy acceleration column. The ion beam which enters the high energy acceleration column after passing through the stripper medium consists of different charge states and these are accelerated to different energies while emerging out of the high energy end of the acceleration column. After a sufficient number of collisions, equilibrium is reached and the average charge and the distribution of charge state fractions do not change
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call