MONITORING DEVICE CAPABLE OF MONITORING THE CENTRING INTENSITY AND UNIFORMITY OF A BEAM OF IONISING RADIATION

摘要

1463891 Ionizing radiation detection and control GGR-MEV 25 Jan 1974 [26 Jan 1973] 03680/74 Heading G1A [Also in Division H4] The intensity, uniformity, and centring of a beam of # or x-rays emitted by an irradiated target are measured by a multi-electrode ionization chamber or chambers. In Fig. 3 there are three chambers 11, 12 and 13 having multiple electrodes E 11 , E 1 2 , E 1 3 respectively. The first two of these each have two electrodes, e.g. e 111 and e 112 separated by an insulating region, while the third multiple electrode E 13 has central and outer electrodes e 131 , e 132 . By adding and subtracting the currents in each electrode, the required information about the incident beam is found. The Fig. 3 embodiment can also give information about the directivity of the beam. Other electrode constructions are suggested, as in Figs. 2, 4, 5, 6.