Hi, I would appreciate it if someone could explain these expressions to me. I was reading about Gas field detectors from " Radiation Detection and Measurements" for "Knoll" and paticulary in chapter five "The gas field detectors are commonly used in dose measurements. In this case, the detector response should be directed toured the conversion of radiation interactions to detector response in dose scale" but what I didn't understand what exactly he mean by : "electron-balance-compensation in the measurement of gamma ray exposure." ? and what's the difference between "free air ionization chamber (for up to 250 keV)" ? "wide range ionization chamber (cavity chamber)" ? .. I couldn't find anything on Google and the book didn't explain very well. Thanks in advance.