Siemens Medical Laboratories, Inc.

Jerry E Chamberlain

Francisco Hernandez

The generation of excessive electron radiation is prevented in an apparatus which comprises an accelerator means for generating and accelerating electrons. The accelerator comprises an electron injector for emitting injector pulses, an electron gun for receiving the injector pulses, a waveguide receiving electrons from the electron gun and a high frequency source for supplying RF signals for the generation of an electric field for accelerating the electrons in the waveguide and generating the electron beam which has a predetermined intensity level according to the amplitudes of the injector pulses. A sensing means senses the amplitudes of the injector pulses and generates sensing signals. The amplitudes of the sensing signals are compared with predetermined reference voltage values and the generation of the electron beam is prevented if the amplitudes of the sensing signals exceed the predetermined reference voltage value.

Apparatus and method for inhibiting the generation of excessive radiation

The generation of excessive electron radiation or X-ray radiation is prevented in an apparatus which comprises an accelerator means for generating and accelerating electrons. These electrons form an electron beam which has a predetermined low intensity level for the generation of electron radiation or a predetermined high intensity level for the generation of X-ray radiation. In case of generating electron radiation a scattering foil or a target, respectively are arranged in the trajectory of the electron beam. The foil and the target are movably arranged on a support means. Detecting means operable by this support means sense the position of the foil and the target relative to the trajectory of said electron beam and inhibiting means prevent the generation of an electron beam having an intensity level which exceeds the predetermined low intensity level if the target is not positioned and/or which exceeds the predetermined high intensity level if the target is positioned in the trajectory of the electron beam.

An ionization chamber for measuring the profile of a radiation field is provided which comprises a first electrode and a second electrode arranged parallel to said first electrode, both electrodes forming a gap therebetween. A shield made of a material opaque to ions produced by the radiation field is movably arranged in said gap between said electrodes and has an aperture, which between said electrodes forms a measuring volume. The ionization chamber further comprises means for moving said shield together with said aperture along said gap between said electrodes.

Ionization chamber for measuring the profile of a radiation field of

The particle accelerator contains an accelerator guide for accelerating particles, an injector for injecting particles into the accelerator guide, a pulsed source of high frequency power which has power adjusting means, a device for introducing the high frequency power from the source into the accelerator guide, a measuring device for measuring particle pulses emitted from the accelerator guide, and a power control circuit connected to the power adjusting means. The power control circuit includes a circuit for supplying an adjusting signal in dependence on the deviation of each particle pulse from an optimum pulse form and a connecting circuitry for connecting the adjusting signal to the power adjusting means. By changing the high frequency power of the source, the form of the measured particle pulses is adjusted towards the optimum pulse form.

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Pittsburg, CA, United States of America

Jerry E Chamberlain