Electron beam deflector system

Claim 1

An arrangement for deflecting the electron beam of a particle accelerator which comprises in combination, a mounting pivotally mounted at the accelerator exit for rotation about the axis of the beam, said mounting securing a first and a second deflector system, said first deflector system having means for deflecting said beam through a first predetermined angle in a given plane, and said second deflector system having means for deflecting said beam through a second angle in said given plane so predetermined that the final direction of said beam intersects the initial direction thereof at an angle at least equal to 90*, said first deflector system having means for deflecting said beam and comprising three electromagnets forming an achromatic system, the respective entry and exit faces of the pole-pieces of said electromagnets making angles different from zero with planes perpendicular to the axis of said beam whereby said deflector system is made convergent, said second deflector system comprising an electromagnet having pole pieces whose entry and exit faces respectively make angles other than zero with planes perpendicular to the beam axis whereby the system is convergent in the plane of the beam, the exit of said second deflector system being a triplet arrangement of quadrupolar magnetic lenses which in the plane of the beam are respectively convergent, divergent and convergent whereby said beam is focused at a point beyond said second deflector system; a target for producing Xrays disposed at said point beyond said second deflector system; a scanning electromagnet having an air-gap disposed in the path of the electron beam between said first and second deflector systems and having coils with means for varying as a function of time the current flowing in said coils; a scanning winding around an electromagnet forming part of said second deflector system; means for varying as a function of time the current flowing in said scanning winding, said scanning electromagnet and said scanning winding disposed normal to each other for producing a cyclical variation of the electron beam impact angle on said target, achieving an X-ray scanning.