Abstract: A neutron ionization chamber of the gamma ray compensation type comprises a neutron-sensing ionization chamber portion having an electrode surface coated with a material for sensing neutrons, a gamma ray-sensing ionization chamber portion which has a low neutron sensitivity in comparison with the neutron sensitivity of said neutron-sensing material, a device for substracting ionization currents in the gamma ray-sensing ionization chamber portion from ionization currents in the neutron-sensing ionization chamber portion, and a coating material which is coated on an electrode surface of the gamma ray-sensing ionization chamber portion, the coating material including a material for sensing neutrons the percentage of which is less than the the percentage of the neutron sensing material of the neutron sensing ionization chamber portion.

Abstract: A radiation counter comprises; electrodes made of nickel base super alloy containing the nickel in the weight ratio exceeding 30% and not exceeding 90% and the chrome, the iron, etc. as the balance; and counter gas in which the argon gas is the chief ingredient and with which the nitrogen gas is mixed in the volume ratio exceeding 2% and not exceeding 30%. The counter operates stably at a high temperature exceeding 450.degree. C., affords relatively large output pulse current and has short electron-collection-time characteristics.

Abstract: Method and apparatus for sensing liquid level of the invention includes a plurality of thermocouple elements that are formed by connecting two kind of thermocouple wires alternately in series into a plurality of thermometric contacts. The two kind of thermocouple wires have different thermoelectric powers SA and SB and have a variety of predetermined lengths. The invention can sense with high reliability a liquid level of a sensed liquid by changing electromotive forces from these thermocouple elements into binary signals by using fewer thermocouple elements than the conventional apparatus. The invention also includes thermocouple elements for parity check to self-diagnose the sensed result to inspect easily and securely errors in operation due to disconnections in the thermocouple elements or external noises.

Abstract: A gamma-ray compensated ionization chamber having cylindrical multiplex electrodes comprises first cylindrical multiplex electrodes and second cylindrical multiplex electrodes being arranged in reverse orders to that of the first cylindrical multiplex electrodes in the longitudinal direction of the cylindrical electrodes to prevent the deterioration of compensating characteristics caused by the variation of an external temperature and variation of gamma-ray spectrum.

Abstract: A resistor of a specific resistance value is inserted between a signal line for transmitting ionization chamber current and a logarithmic amplifier. The specific resistance value is selected to be a proper value so that the value of a negative feedback capacitance of the logarithmic amplifier can be made zero or extremely small without instability phenomena such as an overshoot, ringing or oscillation. Accordingly, it is possible that the response time of a logarithmic measuring apparatus is extremely reduced in a small input-current region.