Mitsubishi Denki Kabushiki Kaisha

Tohoku Electric Power Company, Inc.

Minoru Oda

Kyoichi Miyashita

Mamoru Takada

Sumitaro Arima

Shinji Badono

Hirotsugu Fujiwara

Kunio Ooba

Yukio Nishizawa

Shinzi Badono

Kunio Oba

A gamma-ray compensated ionization chamber wherein the state of compensating a gamma-ray is controlled by utilizing the effect that a change in the applied voltage ratio of a high-voltage electrode to a compensating electrode changes the form of an electric field around the holes in a signal electrode.

Gamma-ray compensated ionization chamber

A pulse shaping filter for use in pulse height analysis, wherein a plurality of semi-gaussian filters of different time constants are provided, which generate a plurality of signals of semi-gaussian shape with different pulse widths from one input signal, and added the plurality of signals after delaying them in a manner that the signal of the semi-gaussian filter of the smaller time constant is delayed longer, thereby to obtain a signal of approximately cusp shaping.

Pulse shaping filter

In a nuclear reactor wherein a plurality of neutron detectors are arranged vertically and at equal azimuth angles around a core of the nuclear reactor, thereby to measure a vertical power profile with a core of the reactor core, the improvement comprising dividing the core into sectors at respective azimuth angles confronting the neutron detectors, usingg the output signal of the partial detectors included in each of the neutron detectors for measuring a vertical reactor power profile of the azimuthal sector of the core confronting the corresponding neutron detector, and averaging the vertical profiles of the respective azimuthal parts with respect to the azimuth angles to measure the vertical reactor power profile of the reactor.

Reactor power measuring method

A computerized tomography system comprising a means for data rearrangement for converting fan-beam projection data into parallel beam projection data speedily andd easily without complicated calculations, said fan-beam projection data obtained at the detecting position corresponding to each defined pitch of rotary angle by which a detector unit comprising a number of radiation detectors arranged in a fan form against the radiation source is rotated.

Computerized tomography system

Described is herein a radiation measuring apparatus in which a detected pulse signal having a wave height value proportional to energy of radiation is transmitted through an optical fiber and a detected pulse signal received from the optical fiber is supplied to an external apparatus. Even if the transmission loss of the optical fiber is subjected to change with passage of time, a monitor pulse signal having a polarity reverse to that of a detected pulse signal is overlapped on the detected pulse signal lest the wave height of the detected pulse signal be not varied on the transmitting side, and a wave height value of a monitor pulse signal passed through the optical fiber is detected to compensate the wave height of the received detected pulse signal using the detected value.

Radiation measuring apparatus

An apparatus for measuring nuclear reactor power distribution comprises a Fourier coefficient calculation means and a transformation means, whereby Fourier coefficients of neutron detector outputs are transformed into Fourier coefficients of integrated values of the reactor power on each interval, and hence conditions required of data for initial calibration are made less severe and the initial calibration is enabled to be performed much easier. The apparatus further comprises an abnormal data deletion means, whereby detection and deletion of abnormal data are made easy so that the apparatus performs a stable operation with high accuracy.

Apparatus for measuring nuclear reactor power distribution

A radiation measuring apparatus capable of producing pulses whose number depends on measured radiation energy and in which the number of pulse height discriminators outputting the pulses is determined by pulse heights or the pulses. The invention makes it possible to compensate sensitivity characteristics of the apparatus against the radiation energy by weighing the number of pulses according to the radiation energy.

A logarithmic amplifier which obtains accurate logarithmic output voltage and expands maximum current value and which realizes accurate logarithmic conversion by eliminating logarithmic conversion error voltage resulting from internal resistance of logarithmic conversion element using a voltage appearing when a forward current of logarithmic conversion element is applied to a resistor.

Logarithmic amplifier

An apochromat type objective lenses, which is applied to an astronomical telescope; a telephoto lens for cameras or the like, comprising a semiapochromatic first lens system synthesized lens composed of two lenses in one group consisting of a convex lens and a concave lens, and an achromatic second lens system synthesized lens composed of two lenses in one group consisting of a concave lens and a convex lens, which is arranged in a spaced apart relation behind the semiapochromatic first lens system; the first and second lens systems being fulfilled with the condition below: ##EQU1## where, f, f: the focal length of the first and second lens systems,

Apochromat type objective lenses

A detecting instrument for detecting time difference between input times of two signals through the use of correlation function is disclosed. The instrument includes a digital circuit for repetitive computing of the correlation function between the two input signals and an analog circuit for detecting the phase of the fundamental frequency component of the repeated correlation function provided by the digital circuit.

Correlation time-difference detector

A signal detection apparatus wherein pulses of the reverse polarity to that of the signal pulse to be detected are detected from an input pulse signal, and thereafter the signal outputting path is cut off for a fixed period, so that noise pulses which have oscillating waveforms in both positive and negative polarites are segregated from the signal pulses which can be provided with a unipolarity, by making use of the difference in polarity, and thereby, the noise pulses are eliminated regardless of their pulse heights. Further, the signal input to the cut-off circuit is delayed for a fixed period of time so that the first peak of the noise pulses may be eliminated even if it is of the same polarity as that of the signal pulse.

Signal detection apparatus

A phase shifter according to this invention comprises circuit groups on a phase advance side and on a phase retardation side in each of which N phase shifting circuits of constant amplitude are connected in cascade, and in which the time constants of the successive phase shifting circuits are set at a geometrical progression of a fixed ratio .alpha., while the time constants of the phase shifting circuits on the phase retardation side are made .beta. times greater than those of the corresponding phase shifting circuits on the phase advance side. Thus, any desired phase difference can be attained according to the value .alpha., while a desired phase difference can be attained according to the value .beta., and the limits of a frequency band width are eliminated by increasing the number of stages N of the cascade connection of each circuit group.

Differential phase shifter

A nuclear reactor output power meter for measuring the output of a nuclear reactor from the concentration signal of radioisotope .sup.16 N in a primary coolant loop, having a transient response correction circuit. This correction circuit includes an approximated normal distribution response filter. This filter has a group delay time substantially corresponding to a single circulation time necessary for the primary coolant loop of the nuclear reactor. This filter also has a rise time in the step response substantially corresponding to a spread in the rise time of the .sup.16 N concentration signal due to agitation occurring during the single circulation time.

Nuclear reactor power meter

This squaring circuit has an input connected to the collector of a PNP transistor which has its emitter connected to the emitter of an NPN transistor. This NPN transistor has the collecotor maintained at a predetermined voltage and the base connected to the base of another NPN transistor. The latter NPN transistor has the collector connected to both a source of constant current and its base, and has the emitter maintained at a predetermined voltage and connected to the emitter of another PNP transistor which has its collector connected to an output of the circuit and its base connected to the base and the collector of the first mentioned PNP transistor which has its collector connected to the input. Both PNP transistors have approximately the same characteristics as both NPN transistors.

Current squaring circuit

A fluorescent X-ray sulfur analyzer is disclosed and includes a radiation source for irradiating a sample with X-rays or .gamma.-rays, a radiation detector for detecting the radiation generated from the sample irradiated by the X-rays or .gamma.-rays and a first analyzer for selecting only fluorescent X-ray pulses from the output of the detector. The analyzer further includes a first pulse rate measuring device for measuring the pulse rate of the pulses selected by the first analyzer, a second analyzer for selecting only pulses of compton scattered rays from the output of the detector and a second pulse rate measuring device for measuring the pulse rate of the pulses selected by the second analyzer. An operational circuit is provided for operating the outputs of the first and second pulse rate measuring devices and is calibrated to compensate for the error caused by the variation of the carbon-hydrogen ratio to realize an accurate weight content of the sulfur in the sample.

Growing community of inventors

Hyogo, Japan

Minoru Oda