Shimadzu Corporation

Akira Arakawa

Junichiro Kozaki

Takahiro Mori

Tsunehiro Inoue

Masaki Ohfuji

Yoshio Tsunazawa

Shigeki Kajihara

Shoichi Okamura

The present invention provides a particle counter capable of accurately discriminating the signal of scattered light by real particles from the background light noise, and furthermore, capable of detecting smaller particles than conventional particle counters. The particle counter according to the present invention includes: a light irradiator for emitting light to the measurement areain a vacuum state or in a near vacuum state; a scattered light detectorfor detecting scattered light generated when the light is delivered to the measurement area; a discriminatorfor determining whether or not a particle exists in the measurement areaby comparing the detection signal of the scattered light detectorand a predetermined discrimination threshold; a vacuum gaugefor measuring the pressure of the measurement area; and the threshold setting unitfor setting a discrimination threshold in accordance with the pressure of the measurement area

Particle counter

The present invention provides a particle counter capable of sensitively determining the contamination level of a light transmission window. The particle counter according to the present invention includes: a light sourcefor emitting light through a light incident windowto a measurement areain a vacuum state or in an approximately vacuum state; a scattered light detectorfor detecting scattered light through a detection window, the scattered light being generated when a light is delivered to the measurement area; a vacuum gaugefor measuring the pressure of the measurement area; a signal processorfor converting a detection signal of the scattered light into an electrical signal; and a contamination level determinerfor determining the contamination level of the transmission window from the time average of the electrical signal and the pressure.

A vacuum pump capable of accurately detecting a rotor temperature based on a change in permeability of a magnetic material. Two targets are fixed to a nut opposed to a gap sensor. The nut is made of pure iron, and a surface of the nut opposed to the gap sensor serves as a target. The target has a Curie temperature greater than a temperature monitoring range, and each of the targets has a Curie temperature falling within the temperature monitoring range. When the targets become opposed to the gap sensor in turn according to rotation of a rotor, three types of signals are output from the gap sensor. The difference-signal generation means generates a difference signal of each the targets, on the basis of a signal of the target. The difference signal is compared with a reference signal Vfor detecting the Curie temperatures to detect a rotor temperature.

Vacuum pump

A vacuum pump includes at least one magnetic body located on a circle about a rotor rotational axis and having a Curie temperature within a rotor temperature monitoring range; an inductance detecting portion facing the circle so as to establish a gap between the circle and the inductance detecting portion, for detecting a change of magnetic permeability of the magnetic body as an inductance change when the magnetic body rotates; and a carrier generation device generating a carrier signal for providing in the inductance detecting portion. An A/D conversion device samples a detection signal of the inductance detecting portion synchronously with a carrier generation by the carrier generation device, and converts the detection signal to a digital signal. A determination device determines whether or not a temperature of the rotor exceeds a predetermined temperature, based on the change of the magnetic permeability of the magnetic body.

A biomagnetism measuring method and apparatus for determining a positional relationship of an examinee with fluxmeters in a short time. A current supply unit simultaneously supplies alternating currents of different frequencies to a plurality of oscillator coils attached to the examinee, respectively. The fluxmeters detect magnetic fields simultaneously formed by the oscillator coils supplied with the currents. Field data thereby obtained are applied through a data collecting unit to a field analyzer for frequency analysis to recognize field strengths due to the respective oscillator coils for the respective fluxmeters. The field analyzer computes positions of the oscillator coils relative to the fluxmeters from the field strengths recognized for the respective oscillator coils and known values of the currents supplied to the respective oscillator coils. Based on this positional information, information indicative of positions of bioelectric current sources measured in a separate process is displayed as superposed on an MRI image of a site of interest of the examinee.

Growing community of inventors

Kyoto, Japan

Akira Arakawa