Hitachi, Ltd.

Hiroaki Sakurabata

Manabu Matsumoto

Kazuyoshi Saito

Toshiaki Kobari

Mamoru Katane

Nobuo Hirano

Shiro Matsuzaki

Kazuo Hiramoto

Masahiro Tadokoro

Junichi Hirota

A particle beam therapy system includes a synchrotron which accelerates beams of charged particles to a desired energy level and permits extraction of the beams of charged particles exceeding a stability limit, an irradiation device which irradiates an object with the beams of charged particles, a beam transport system which conducts the beams of charged particles extracted from the synchrotron to the irradiation device, and a control unit which provides control to remove part of the beams of charged particles circling in the synchrotron and allow the rest of the circling beams of charged particles to be extracted from the synchrotron and conducted to the irradiation device. The particle beam therapy system produces irradiation beams suitable for high-precision particle beam therapy by the spot scanning method or the like.

Particle beam therapy system

A particle beam therapy system using a spot scanning method includes a synchrotron, a beam transport system, an irradiation system, and a controller. A controller is configured to turn on a radio frequency electromagnetic field to be applied to an extraction system when a charged particle beam is to be supplied to the irradiation system, and turn off the radio frequency electromagnetic field to be applied to the extraction system when the supply of the charged particle beam to the irradiation system is to be blocked by means of an electromagnet provided in the beam transport system or in the synchrotron. The controller is also adapted to turn off a radio frequency acceleration voltage to be applied to an acceleration cavity in synchronization with the turning-off of the radio frequency electromagnetic field to be applied to the extraction device.

An apparatus for treating the inner surface of a vacuum chamber includes a support, means for anchoring the vacuum chamber to the support and holding the vacuum chamber, a broach having a plurality of cutting edges having cutouts, and broach drive means to which the broach arranged on the support is fitted. The broach drive means unidirectionally moves the broach relatively to the vacuum chamber in an axial direction to cut off a contaminated layer on an inner surface of the vacuum chamber. The outer diameter of each cutting edge, excluding the cutouts, is set greater than that of an immediately preceding one in a direction of a rearmost edge face from a front edge face. The apparatus may also include means for supplying an inert gas or a mixture of nitrogen and inert gases to a surface of the vacuum chamber being treated by the broach, or means for supplying a lower alcohol for dissolving contaminants contained in the contaminated layer to the surface of the vacuum chamber being treated by the broach.

Apparatus for treating the inner surface of vacuum chamber

The present invention provides apparatus for acceleration of a charged particle beam which includes energy means for altering the energy of a circulating beam circulating in the apparatus and means for extracting output beams from the apparatus. Control means are arranged to be operable to alter the energy of the circulating beam using the energy means so as to be able to extract output beams of at least two energies from the apparatus using the means for extracting. Thus there is provided an accelerator, and an extraction method therefor, which is capable of extracting a small diameter beam having a varying energy level. This facilitates improved medical irradiation treatment using the beam.

Particle beam accelerator, and a method of operation

A rod driver is used to drive a rod so as to move a broach through a continuous vacuum chamber in the axial direction. The broach is provided at the leading end of the rod with cutting and finishing edges at a plurality of stages in the axial direction. The cutting edges each have chip breakers in their outer periphery. The broach is moved in the vacuum chamber to cut the inner surface of the vacuum chamber, so that a new surface is formed. During the cutting at least one of an inert gas, nitrogen, and a mixture of the inert gas and nitrogen is supplied to the cutting edges. The outer diameter of the finishing edge is same as the desired inner diameter of the vacuum chamber and the finishing edges are effective in forming such a vacuum chamber with greater precision and the least friction. As a contaminated and decomposed layer on the inner surface of the vacuum chamber is removed in the axial direction of the inner surface of the vacuum chamber for certain, moreover, gas desorption, from a new surface, originating from thermal desorption and photodesorption generated at the time of synchrotron radiation can be minimized to satisfy a requirement for a vacuum vessel.

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Hitachi, Japan

Hiroaki Sakurabata