A beam-energy checking device for electron beams from radiotherapy accelerators

The present paper describes the development of a beam-energy checking device based on the Johnsen method. The reason of which is the simplicity and the linear energy response of the device. Although Johnsen used ionization current and integrated charges for output signal of the ion chambers, we used pulse signal derived from the chambers in addition to the average ion current. Pulse characteristics of the electron beams from radiotherapy accelerators could be studied using this pulse readout from the chambers. (J.P.N.)