title: Research and development of an electron beam focusing system for a high-brightness X-ray generator.
abstract: A new type of rotating anticathode X-ray generator, where an electron beam of up to 60 keV irradiates the inner surface of a U-shaped Cu anticathode, has achieved a beam brilliance of 130 kW mm(-2) (at 2.3 kW). A higher-flux electron beam is expected from simulation by optimizing the geometry of a combined-function-type magnet instead of the fringing field of the bending magnet. In order to minimize the size of the X-ray source the electron beam has been focused over a short distance by a new combined-function bending magnet, whose geometrical shape was determined by simulation using the Opera-3D, General Particle Tracer and CST-STUDIO codes. The result of the simulation clearly shows that the role of combined functions in both the bending and the steering magnets is important for focusing the beam to a small size. FWHM sizes of the beam are predicted by simulation to be 0.45 mm (horizontal) and 0.05 mm (vertical) for a 120 keV/75 mA beam, of which the effective brilliance is about 500 kW mm(-2) on the supposition of a two-dimensional Gaussian distribution. High-power tests have begun using a high-voltage 120 kV/75 mA power supply for the X-ray generator instead of 60 kV/100 mA. The beam focus size on the target will be verified in the experiments.
authors.affiliation: Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan. takeshi.sakai@kek.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ohsawa
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Sakabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugimura
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ikeda
mesh_terms: D004583:Electrons; D004867:Equipment Design; D017356:Synchrotrons / Q000295:instrumentation*; D014965:X-Rays