Frequency characteristic of an aspiration integrating small ion counter with a shielded collector

In the paper the frequency response of the Gerdien tube with a shielded collector was derived. The frequency response of the tube was defined as the ratio of the complex amplitude of the collector current to the complex amplitude of ion concentration at the inlet surface K( jω)=Ic( jω)/n( jω). It was found as a system response to impulse ion concentration excitation. The shape sin( fτ)/( fτ) of the frequency response was obtained ( f is the frequency of time varying ion concentration and τ the time of the flight of ions from the inlet to the collector). The results can be useful for designing ion counters with a modulated ion stream.