What happens to the fill gas in an ionization chamber? Once incident radiation has created an ion pair, which has then moved to its opposite polarity electrode, is that ion pair removed from the fill gas? So if enough incident radiation is detected over a period of time all the gas would be ionized and a vacuum left in its place? What then happens to the positive ion? Is it consumed in the same circuit the electron is? (The circuit that produces a representation of the incident radiation for the operator) If this isn't the case, when does the ion pair recombine whilst still giving an indication to the ionization chamber operator that radiation has been detected?