Abstract: [Problems to be Solved] A fluoride which emits light with high brightness in a vacuum ultraviolet region is provided. Also provided are a novel vacuum ultraviolet light emitting element which comprises the fluoride and which can be suitably used in photolithography, cleaning of a semiconductor or liquid crystal substrate, sterilization, next-generation large-capacity optical disks, medical care (ophthalmologic treatment, DNA cleavage), etc.; and a vacuum ultraviolet light emitting scintillator which is composed of the fluoride and can be suitably used in a small-sized radiation detector incorporating a diamond light receiving element or AlGaN light receiving element with a low background noise as an alternative to a conventional photomultiplier tube. [Means to Solve the Problems] A metal fluoride crystal represented by a chemical formula K3-XNaXTmYZLuY(1-Z)F3+3Y where 0.7<X<1.3, 0.85<Y<1.1 and 0.001?Z<1.0, such as K2NaTm0.4Lu0.6F6, K2.1Na0.9TmF6, K2NaTmF6, or K2NaTm0.9F5.

Abstract: A vacuum ultraviolet light emitting device comprising: a luminescence substrate which is composed of a transparent substrate of lithium fluoride, magnesium fluoride, calcium fluoride, barium fluoride or the like, and a metal fluoride thin-film layer formed on the transparent substrate and being a thin-film layer of a metal fluoride such as LuLiF4, LaF3, BaF2 or CaF2, the metal fluoride being doped with atoms of neodymium (Nd), thulium (Tm), erbium (Er) or the like; and an electron beam source such as a thermionic emission gun or a field emission gun, wherein the luminescence substrate and the electron beam source are disposed in a vacuum atmosphere, and the metal fluoride thin-film layer is irradiated with electron beams from the electron beam source to emit light including wavelength components of vacuum ultraviolet light.

Abstract: The optical disc apparatus of this invention includes: an optical pickup, which irradiates an optical disc with a light beam and generates a light detection signal based on the beam reflected from the disc; a search section, which controls the pickup before data is written on a storage area of the disc, thereby adjusting the beam spot location and searching a reference one of information layers stacked for a defective area in the storage area of the disc; a defect decision section for detecting an error based on the detection signal and determining a portion of the storage area, where the error has occurred, as the defective area; a defect size measuring section for measuring the size of the defective area in an area of the reference layer and generating a defect information list indicating there is the defective area in the area of the reference layer; and a recording range control section for managing, by reference to the list, the storage area such that no data will be written on a perpendicularly projecte

Abstract: A neutron measurement apparatus 1A includes a neutron detection unit 10, a photodetection unit 20 that detects scintillation light emitted from the neutron detection unit 10, a light guide optical system 15 that guides the scintillation light from the neutron detection unit 10 to the photodetection unit 20, and a shielding member 30 which is located between the neutron detection unit 10 and the photodetection unit 20 for shielding radiation passing in a direction toward the photodetection unit 20. Further, a scintillator formed of a lithium glass material in which PrF3 is doped to a glass material 20Al(PO3)3-80LiF is used as a neutron detection scintillator composing the neutron detection unit 10. Thereby, the neutron detection scintillator and the neutron measurement apparatus which are capable of suitably performing neutron measurement such as measurement of scattered neutrons from an implosion plasma can be realized.

Abstract: [Problems to be Solved] The present invention aims to provide a scintillator which can detect photons of high energy, such as hard X-rays or ?-rays, with high sensitivity. [Means to Solve the Problems] A scintillator comprises lithium lutetium fluoride containing neodymium as a luminescence center, the lithium lutetium fluoride being represented by the chemical formula LiLu1-xNdxF4 where x is in the range of 0.00001 to 0.2, preferably, 0.0001 to 0.05. Preferably, the scintillator comprises a single crystal of the lithium lutetium fluoride containing neodymium.

Abstract: Provided are a multilayer ZnO single crystal scintillator wherein the light emitting quantity is increased, and a method for manufacturing such scintillator. A multilayer body composed of ZnO semiconductor layers having different band gaps is manufactured, and a layer having a small band gap is made to have a thickness that permits ionization radiation, such as ? rays and electronic rays, to enter the layer, thereby the light emitting quantity of the multilayer ZnO single crystal scintillator is greatly increased.

Abstract: An optical disk drive includes: an objective lens for converging a light beam onto an optical disk with an information storage layer; an actuator for moving the lens perpendicularly to the storage layer; an actuator driver for moving the lens at a predetermined velocity by controlling the actuator's operation; and a disk position detector for detecting the position of the lens, when the focal point of the beam is located on the storage layer, as a disk position. While the lens is being moved toward the disk to perform a focus finding operation, the moving velocity of the lens is set high until the lens reaches a velocity switching point, determined by reference to the disk position, and is set low once the lens has passed the point. The switching point is set farther away from the disk than the position of the lens is when the focal point of the beam is located on the storage layer of the disk.

Abstract: [Problems to be Solved] It is an object of the present invention to provide a novel radiographic image detector which can detect radiation, such as hard X-rays or ?-rays, with high sensitivity and which is excellent in position resolution and count rate characteristic. [Means to Solve the Problems] A radiographic image detector comprises a combination of a scintillator, such as a lanthanum fluoride crystal containing neodymium, for converting incident radiation into ultraviolet rays; and a gas multiplication ultraviolet image detector for converting ultraviolet rays into electrons, amplifying such electrons by use of a gas electron avalanche phenomenon, and detecting the electrons.

Abstract: An optical disc drive according to the present invention can write data on both a write-once disc and a rewritable disc. The drive includes: a disc recognizing section 110 for recognizing the type of a given optical disc as a write-once disc or a rewritable disc; and track skipping detection signal generating section, which outputs track skipping detection signal when a first condition on tracking error is satisfied if the given optical disc, on which data is being written, has turned out to be a write-once disc. On the other hand, if the given optical disc has turned out to be a rewritable disc, the track skipping detection signal generating section outputs track skipping detection signal when a second condition on tracking error, which is different from the first condition, is satisfied. A control section stops writing the data in response to the track skipping detection signal while the data is being written.

Abstract: A scintillator for neutron detection, comprising a metal fluoride crystal containing, as constituent elements, a metal having a valence of 2 or higher, such as calcium, aluminum or yttrium; lithium; and fluorine, the metal fluoride crystal containing 1.1 to 20 atoms per unit volume (atoms/nm3) of 6Li, having an effective atomic number of 10 to 40, containing a lanthanoid such as cerium, praseodymium or europium, and being represented by, for instance, LiCaAlF6, LiSrAlF6 and LiYF4. The scintillator for neutron detection has high sensitivity to neutron rays, and is reduced in a background noise attributed to ? rays.

Abstract: An optical disc apparatus includes: a defect detecting section 124 for detecting, based on a light detection signal and with respect to a preset detection reference level, a fingerprint or a bubble on the disc 102 as a defect to output a defect detection signal; and a waveform shaping section 126 to output a hold signal that holds, in response to the defect detection signal, a signal from a tracking control section 109 at a level just before the defect has occurred. The apparatus is initially operated not to hold the signal from the tracking control section 109 even if there is a defect. But once a tracking failure has occurred during a read operation, settings are changed to hold the signal from the tracking control section 109 against the defect while the read operation is retried.

Abstract: A material for high-temperature region piezoelectric device that can be used at a high temperature zone exceeding 400 DEG C, having a resistivity whose temperature dependence is slight. The material is characterized by having a composition selected from the group consisting of RE3Ga5?xAlxSiO14 (wherein RE represents a rare earth, and 0<X<5), RE3Ta0.5Ga5.5?xAlxO14 (wherein RE represents a rare earth, and 0<X<5.5) and RE3Nb0.5Ga5.5?xAlxO14 (wherein RE represents a rare earth, and 0<x<5.5) and by exhibiting a 100 to 600° C. resistivity change of ?104. The process for producing the same is characterized by growing a single crystal from a solution in an atmosphere of inert gas containing an oxidative gas and thereafter cooling the single crystal in an inert gas whose oxidative gas molar fraction (z) is lower than in the above growing step.

Abstract: An optical disk device of the present application includes: a turntable 30 including plural induction grooves 31a to 31h as concave portions radially extending from vicinity of a center of the turntable 30 and having open portions in an outer periphery of the turntable 30 and plural through-holes 32a to 32h penetrating bottom faces 33a to 33h on the vicinity of the center side of the plural induction grooves 31a to 31h and a top face of the turntable 30; and an outer rotor type spindle motor 35 provided with plural fins 36a to 36h as convex portions on a rotor on a side face thereof. The optical disk device of the present application utilizes an airflow generated by rotation of the rotor of the spindle motor 35 and the turntable 30 in conjunction therewith as a dust removing wind for removing dust attaching to an objective lens side area.

Abstract: An optical disk apparatus according to the present invention is capable of reading data from an optical disk 102 which has a plurality of information recording layers, including a first information recording layer whose distance from a disk surface is relatively small and a second information recording layer whose distance from the disk surface is relatively large. This optical disk apparatus includes: a focus control section 117 for causing a converging point of the light beam to be positioned on an arbitrary information recording layer of the optical disk 102; a tracking control section 118 for causing the converging point of the light beam to be positioned on a predetermined track of the information recording layer; and a gain switching section 108 capable of changing gain characteristics of at least one of the focus control section 117 and the tracking control section 118.

Abstract: To provide a scintillator for neutron detection which has high sensitivity to neutron rays, and is reduced in a background noise attributed to ? rays. [Means to Solve the Problems] A scintillator for neutron detection, comprising a metal fluoride crystal containing, as constituent elements, a metal having a valence of 2 or higher, such as calcium, aluminum or yttrium; lithium; and fluorine, the metal fluoride crystal containing 1.1 to 20 atoms per unit volume (atoms/nm3) of 6Li, having an effective atomic number of 10 to 40, containing a lanthanoid such as cerium, praseodymium or europium, and being represented by LiCaAlF6, LiSrAlF6, LiYF4 etc.

Abstract: In an optical pickup driving apparatus and method, a moving device is controlled when an objective lens is moved toward a recording surface and it is detected that the voltage of the focus error signal has reached a slice level voltage H corresponding to displacement of predetermined magnitude from a reference potential E. The objective lens is moved toward the recording surface by a maximum of an upper limit of a predetermined amount of movement and when the amount of movement of the objective lens reaches the predetermined amount of movement, so as to move the objective lens away from the recording surface. And when it is detected during a period of backward movement of the objective lens, that the voltage of the focus error signal has reached the second slice level voltage H corresponding to displacement of predetermined magnitude from the reference potential E, control of beam spot positioning is performed so as to focus an optical spot.

Abstract: A radiation detecting apparatus of the present invention is an apparatus comprising a scintillator for converting incident radiation into ultraviolet radiation having a wavelength of 220 nm or less, the scintillator being composed of, for example, Nd-doped LaF3 crystals; and a diamond thin film sensor for guiding the resulting ultraviolet radiation and converting it into an electrical signal, the radiation detecting apparatus being adapted to transform the incident radiation to the electrical signal. The radiation detecting apparatus can detect radiation, such as X-rays, ? rays, ? rays, ? rays, or neutron rays, with high sensitivity. The radiation detecting apparatus also has a fast response, is very easy to downsize, has high resistance to radiation, and can be preferably used in the medical field, the industrial field, or the security field.

Abstract: A method for producing a nitride semiconductor, comprising controlling temperature and pressure in a autoclave containing a seed having a hexagonal crystal structure, a nitrogen element-containing solvent, a raw material substance containing a metal element of Group 13 of the Periodic Table, and a mineralizer so as to put said solvent into a supercritical state and/or a subcritical state and thereby ammonothermally grow a nitride semiconductor crystal on the surface of said seed, wherein the crystal growth rate in the m-axis direction on said seed is 1.5 times or more the crystal growth rate in the c-axis direction on said seed. By the method, a nitride semiconductor having a large-diameter C plane or a nitride semiconductor thick in the m-axis direction can be efficiently and simply produced.

Abstract: Disclosed is a method for preparing lactic acid bacteria having a high anti-allergic activity comprising culturing the lactic acid bacteria in a medium containing casein hydrolysate. The invention also provides an anti-allergic agent and a food/beverage product having anti-allergic activity comprising the lactic acid bacteria cultured in the method of the invention.

Abstract: A radiation detection apparatus comprising a scintillator composed of a lanthanum fluoride crystal containing neodymium or a lithium barium fluoride crystal containing neodymium, for converting incident radiation into ultraviolet ray and a micro-strip gas chamber for converting the incident ultraviolet ray into an electric signal and capable of extracting the radiation as an electric signal. The radiation detection apparatus which has excellent spatial resolution and can detect even a high-energy photon at high sensitivity is provided at low cost.