Gas Amplification Region Summary

DETECTOR VOLTAGE Radiation Detectors Summary The alpha curve is higher than the beta curve from Region I to part of Region IV due to the larger number of ion pairs produced by the initial reaction of the incident radiation. Detector voltage principles are summarized below. Gas Amplification Region Summary Recombination Region The voltage is such a low value that recombination takes place before most of the negative ions are collected by the electrode. Ionization Region The voltage is sufficient to ensure all ion pairs produced by the incident radiation are collected. No gas amplification takes place. Proportional Region The voltage is sufficient to ensure all ion pairs produced by the incident radiation are collected. Amount of gas amplification is proportional to the applied voltage. Limited Proportional Region As voltage increases, additional processes occur leading to increased ionizations. Since positive ions remain near their point of origin, further avalanches are impossible. Geiger-Müller Region The ion pair production is independent of the radiation, causing the initial ionization. The field strength is so great that the discharge continues to spread until amplification cannot occur, due to a dense positive ion sheath surrounding the central wire. Continuous Discharge Region The applied voltage is so high that, once ionization takes place, there is a continuous discharge of electricity. IC-06 Page 18 Rev. 0