System for monitoring the position, intensity, uniformity and directivity of a beam of ionizing radiation

#This application contains subject matter disclosed in my copending application Ser. No. 243,208 filed Apr. 12, 1972, now U.S. Pat. No. 3,808,441.

#The present invention relates to devices for monitoring beams of ionizing radiation and more particulary to a safety system including means for precisely determining the position of such a beam in relation to a target, as well as its intensity, 5 its uniformity and its directivity.

#This device can be utilized equally for a beam of charged particles (beta rays, formed by electrons) and for a beam of uncharged particles ( X-rays constituted by photons ).

#FIG. 1 illustrates an embodiment of a monitoring device in accordance with the invention;

#FIG. 2 illustrates in detail an electrode of the monitoring device shown in FIG. 1;

#FIGS. 3, 4, 5, 6 illustrate other embodiments of a monitoring device in accordance with the invention; and

#In the embodiment shown in FIG. 1, the monitoring device in accordance with the invention comprises an ionization chamber 1 constituted by a metal cylinder closed at its ends by a thin wall, transparent to an incident beam of ionizing radiation, chamber 1 being provided with an electrode 2 constituted by eight elements electrically insulated from one another.

#FIG. 2, in a more detailed fashion, shows this electrode 2 which can be realized with a sheet of polyethylene-terephthalate, commercially known as "MYLAR," upon which, by vaporization under vacuum for example, a metal film has been deposited. Insulating strips B (e.g. non-metallized portions of the sheet) separate the various elements e.sub.1, e.sub.2, e.sub.3, . . . , e.sub.8 constituting the electrode 2, these elements being provided with respective output leads s.sub.1, s.sub.2, s.sub.3, . . . , s.sub.8 each connected to an amplifier (not shown in this Figure ) converting the relatively weak ion currents picked up by each of the elements e.sub.1, e.sub.2, e.sub.3 . . . , e.sub.8 signals wich can readily be processed.

#This embodiment requires eight amplifiers. However, it does not introduce any redundancy into the measurements, and a redundancy is sometimes required.