Magnetic beam deflection system and method
AssigneeMitsubishi Jukogyo Kabushiki Kaisha
InventorsIchiro Yamashita, Ikuo Wakamoto, Susumu Urano, Yuichiro Kaminou
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Abstract
A deflection magnetic system and method are provided to deflect an electron beam through a predetermined angle while maintaining a circular cross-section for the electron beam. A plurality of spaced magnetic fields are provided to deflect the electron beam through angles less than the total predetermined angle, but the total angle is achieved when the beam passes through the last magnetic field. Magnetic shields are provided between the spaced magnetic fields to absorb any undesired leakage magnetic flux.
Claims12
A magnetic beam deflection system for deflecting a charged particle beam through an angle of substantially 270.degree., said system comprising:
- three spaced magnets for respectively generating spaced magnetic fields arranged along a trajectory of the charged particle beam, each of said magnetic fields deflecting the charged particle beam through an angle less than 270.degree., the total angle of said charged particle beam deflected by said magnetic fields is equal to substantially 270.degree.;
- a main coil arranged around all of said magnets for simultaneously generating primary magnetic fields in said magnets;
- a first supporting coil arranged around at least one of said magnets to adjust the intensity of said primary magnetic field in said one magnet;
- and
- a plurality of magnetic shields, one of said magnetic shields being arranged respectively between adjacent said spaced magnets.
A method for deflecting a charged particle beam through an angle of substantially 270.degree., said method comprising the steps of:
- simultaneously generating three spaced primary magnetic fields arranged along a trajectory of the charged particle beam, each of said primary magnetic fields deflecting said charged particle beam through an angle less than 270.degree., the total angle of said charged particle beam deflected by said primary magnetic fields is equal to substantially 270.degree.;
- generating a first secondary magnetic field for adjusting the intensity of at least one of said primary magnetic fields;
- and
- absorbing any stray leakage magnetic flux that occurs between said spaced primary magnetic fields.
Dependencies are inferred from the claim text.