TIME RESOLVING IONIZATION MONITOR FOR MICROSECOND RADIATION IMPULSES

The current induced in the outer circuit of a fast response ionization chamber exposed to pulsed radiation consists of two components, a fas t one induced by free electrons and a slow one induced by ions. The fa st electron component may be used for the representation of the shape of the ionizing pulse. In order to avoid interference with the slow io n current, the latter has to be removed from the signal. This is achie ved by deriving a voltage course from the chamber signal which fits th e shape of the ion component and subtracting this from the entire sign al. The function of the electronic circuit used for this purpose is de scribed. Some considerations about the time resolution of the chamber gas are to be found in the appendix.