Elimination of Ballistic Deficits for Ionization Chamber Pulses by using Trapezoidal Pulse shaper

摘要

In a typical charged particle spectrometer employing charge sensitive preamplifier, the ballistic deficits can noticeably reduce the resolution of spectrometer when the pulse shaping networks produce short pulses with sharp peaks. Recently, it has been demonstrated that the effect of ballistic deficit can be eliminated by using flat-topped shapes. We have made simulation of the voltage pulses from the two-electrode parallel plate ionization chamber as well as pulses from the gridded parallel plate ionization chamber for heavy ions in order to understand the importance of flat-topped shapes in eliminating the effect of ballistic deficit. These detector pulses have been processed through preamplifier and CR-differentiator having pole-zero cancellation followed by a combination of rectangular and truncated ramp shaping network. The simulations of the voltage pulses have been made using numerical integration method for different angles the heavy ion track makes with the electric field. The simulations clearly show that the dependence of ballistic deficit on the angle of the charged particle track with electric field can be made negligibly small by using trapezoidal pulse shaper.