Osaka University

Mitsubishi Heavy Industries Mechatronics Systems, Ltd.

Mitsubishi Jukogyo Kabushiki Kaisha

Shuhei Kuri

Isao Murata

Hiroshi Horiike

Eiji Hoashi

Sachiko Doi

Toshiharu Takahashi

Takashi Ishide

Takashi Akaba

Tadashi Nagashima

Isao Shirasu

Yoshio Hashimoto

Yasumi Nagura

Shoichi Hamada

Itsuro Kato

Seiichi Kawaguchi

Takuya Kidera

Provided are a neutron monitor device and a neutron measurement method which make it easier to measure the intensity of the neutrons having the energy region of 10 KeV to several hundreds KeV. A neutron monitor device includes a first detector which includes a hemispherical first body formed of PE and having a radius of 31 mm, a first specimen containing GaN disposed at the center of the first body, a Cd layer provided on an outer surface of the first body, and a B layer provided inside the first body, and a second detector which includes a hemispherical second body formed of PE and having a radius of 27 mm, a second specimen containing GaN disposed at the center of the second body, a B layer provided on the outer surface of the second body, and a Cd layer provided inside the second body.

Neutron monitor device and neutron measurement method

The neutron irradiation apparatus includes an introduction tube for introducing a proton beam, a target structure provided in a lower end of the introduction tube, an aluminum fluoride layer disposed below the target structure in an irradiation path of neutrons generated in the target structure, and a heavy water layer placed under the aluminum fluoride layer in layers. The aluminum fluoride layer is set at a thickness that increases epithermal neutrons. Since use of only the aluminum fluoride layer increases its thickness too much, heavy water is placed. Heavy water moderates neutrons quickly, and allows increasing epithermal neutrons without increasing the thickness. The combination of the aluminum fluoride layer and the heavy water layer allows increasing epithermal neutrons by attenuating only fast neutrons without increasing thermal neutrons. Accordingly, neutron flux with many epithermal neutrons is obtained.

Neutron control device and neutron irradiation apparatus

The known reflecting mirror for a laser beam conisting of a mirror base member and a high-reflectivity metal coating layer formed on the mirror base member for reflecting a laser beam, is improved so as to maintain a high mirror reflectivity without necessitating a cooling facility. The improvements reside in that a coating layer having a small diffusion coefficient is provided on the back surface side of the high-reflectivity metal coating layer, and/or in that at least one layer of dielectric coating layer or layers are provided on the surface of the high reflectivity metal coating layer. Also, an improved laser beam welding apparatus for an inner circumferential surface of a tube is provided by employing the aforementioned improved reflection mirror as a reflecting mirror in an optical condensing system included in a laser beam welding apparatus for an inner circumferential surface of a tube, which apparatus comprises a flexible tube including an optical fiber extended therethrough for transmitting a welding laser beam, said flexible tube being insertable into a work tube, a position detector for detecting a relative position of the flexible tube with respect to the work tube and fixing means of internally expansible type for fixing the flexible tube within the work tube, respectively provided at the front end portion of the flexible tube, a rotary cylinder rotatably supported from the flexible tube, guide support means mounted to the rotary cylinder in a relatively rotatable manner and being able to be held in contact with the inner wall surface of the work tube for holding the rotary cylinder concentrically with the work tube, rotary drive means having its output shaft disposed coaxially with said rotary cylinder for rotationally driving the rotary cylinder, an optical condensing system disposed within said rotary cylinder for leading the welding laser beam emanating from the front end of the optical fiber to the inner wall surface of the work tube in a condensed state, gas scavenging means for discharging metal vapor produced upon welding of the work tube, and gas cooling means for cooling the optical condensing system.

Reflecting mirror for a laser beam and laser beam welding apparatus,

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Kobe, Japan

Shuhei Kuri