1 research outputs found
Pulsed extraction of ionization from helium buffer gas
The migration of intense ionization created in helium buffer gas under the
influence of applied electric fields is considered. First the chemical
evolution of the ionization created by fast heavy-ion beams is described.
Straight forward estimates of the lifetimes for charge exchange indicate a
clear suppression of charge exchange during ion migration in low pressure
helium. Then self-consistent calculations of the migration of the ions in the
electric field of a gas-filled cell at the National Superconducting Cyclotron
Laboratory (NSCL) using a Particle-In-Cell computer code are presented. The
results of the calculations are compared to measurements of the extracted ion
current caused by beam pulses injected into the NSCL gas cell.Comment: Accepted for pubilication in Nucl. Instrum. Meth. B, 14 pages, 8
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