Abstract: A radiation detector includes: a detector case which has an opening portion, a reflector which is attached to the opening portion of the detector case, a plastic scintillator which is disposed inside of the detector case, with a clearance from the reflector, a light guide into which fluorescence emitted from the plastic scintillator enters, a photo multiplier tube at which the fluorescence having passed through the light guide enters, and a pre amplifier which converts an output of the photo multiplier tube into a current pulse; wherein the plastic scintillator or the light guide has a soaked layer of ammonia which is formed on a surface thereof. This radiation detector is improved in the chemical resistance to the process fluid which includes a corrosive gas.

Abstract: A radiation detector includes: a detector case which has an opening portion, a reflector which is attached to the opening portion of the detector case, a plastic scintillator which is disposed inside of the detector case, with a clearance from the reflector, a light guide into which fluorescence emitted from the plastic scintillator enters, a photo multiplier tube at which the fluorescence having passed through the light guide enters, and a pre amplifier which converts an output of the photo multiplier tube into a current pulse; wherein the plastic scintillator or the light guide has a soaked layer of ammonia which is formed on a surface thereof. This radiation detector is improved in the chemical resistance to the process fluid which includes a corrosive gas.

Abstract: A radiation measurement device having a radiation detector, a measurement instrument provided with a signal conversion unit for carrying out signal conversion on a detection current signal output from the radiation detector, and a signal input line for supplying the detection current signal output from the radiation detector to the signal conversion unit, wherein if a test mode is selected, a test current signal is superposed on the detection current signal and supplied to the signal conversion unit through the closing of contacts and the connection of a constant-voltage source and the signal input line, and if a normal mode is selected, the constant-voltage source is connected to a point having the same potential as the signal input line and the generation of a potential difference between the contacts is prevented through the opening of the contacts and the disconnection of the constant-voltage source and signal input line.

Abstract: A radiation measurement device having a radiation detector, a measurement instrument provided with a signal conversion unit for carrying out signal conversion on a detection current signal output from the radiation detector, and a signal input line for supplying the detection current signal output from the radiation detector to the signal conversion unit, wherein if a test mode is selected, a test current signal is superposed on the detection current signal and supplied to the signal conversion unit through the closing of contacts and the connection of a constant-voltage source and the signal input line, and if a normal mode is selected, the constant-voltage source is connected to a point having the same potential as the signal input line and the generation of a potential difference between the contacts is prevented through the opening of the contacts and the disconnection of the constant-voltage source and signal input line.

Abstract: A dose rate monitoring device contains a first radiation detector including an inorganic crystal scintillator, a second radiation detector including a plastic scintillator, a detector mount having a cylinder part, a low range calculator calculating a first compensation dose rate of an incident radioactive ray based on the detection signal pulse, a high range calculator calculating a second compensation dose rate of an incident radioactive ray based on the detection signal pulse, a dose rate calculator calculating a dose rate ratio from the first compensation dose rate and the second compensation dose rate, and choosing a compensation dose rate according to the magnitude of the calculated dose rate ratio; and a display displaying the compensation dose rate which is outputted from the dose rate calculator, wherein the plastic scintillator which is included in the second radiation detector is wound around the cylinder part of the detector mount.

Abstract: A dose rate monitoring device contains a first radiation detector including an inorganic crystal scintillator, a second radiation detector including a plastic scintillator, a detector mount having a cylinder part, a low range calculator calculating a first compensation dose rate of an incident radioactive ray based on the detection signal pulse, a high range calculator calculating a second compensation dose rate of an incident radioactive ray based on the detection signal pulse, a dose rate calculator calculating a dose rate ratio from the first compensation dose rate and the second compensation dose rate, and choosing a compensation dose rate according to the magnitude of the calculated dose rate ratio; and a display displaying the compensation dose rate which is outputted from the dose calculator, wherein the plastic scintillator which is included in the second radiation detector is wound around the cylinder part of the detector mount.

Abstract: A radiation monitoring device comprises a radiation monitor and a test unit for testing the radiation monitor. The radiation monitor includes a radiation detector and a measurement unit. The test unit includes a test pulse generator and a test pulse controller. The measurement unit includes a counter circuit, a computing part that computes a count rate with the standard deviation kept constant, an input switching circuit. When a test mode is selected in the radiation monitor, the test pulse controller changes the repetition frequency of test pulses in a step-function manner to the same repetition frequency of a start count rate specified as reference, replaces a count rate in the computing part at current computing cycle with the start count rate, switches the input switching circuit to the test pulse input at next computing cycle to start the test, and then finishes the test after a predetermined time elapses.

Abstract: A shield has a detector installing hole having a central axis orthogonal to a central axis of a detection tube. A radiation sensor of a columnar scintillation detector to which a low concentration side measurement range within all required measurement ranges is allocated is arranged inside the detector installing hole. An ionization chamber to which a high concentration side measurement range is allocated is arranged side by side in parallel with the detection tube. The measurement range of the columnar scintillation detector and the measurement range of the ionization chamber are adjusted so as to be overlapped with each other.

Abstract: A sampling unit that samples a sample gas includes an intake pipe that takes in a sample gas, and a mist/dust elimination unit that eliminates mist produced when steam in a sample gas condenses in the intake pipe and dust, creates a drain including dust, and separates the drain from the sample gas; mist wets fibers loaded therein in a stacked manner so that a water film produced on the surface of the fibers collects dust, and the water film grows to water drops and become drains so that the dust is exhausted and eliminated.

Abstract: A sampling unit that samples a sample gas includes an intake pipe that takes in a sample gas, and a mist/dust elimination unit that eliminates mist produced when steam in a sample gas condenses in the intake pipe and dust, creates a drain including dust, and separates the drain from the sample gas; mist wets fibers loaded therein in a stacked manner so that a water film produced on the surface of the fibers collects dust, and the water film grows to water drops and become drains so that the dust is exhausted and eliminated.

Abstract: A shield has a detector installing hole having a central axis orthogonal to a central axis of a detection tube. A radiation sensor of a columnar scintillation detector to which a low concentration side measurement range within all required measurement ranges is allocated is arranged inside the detector installing hole. An ionization chamber to which a high concentration side measurement range is allocated is arranged side by side in parallel with the detection tube. The measurement range of the columnar scintillation detector and the measurement range of the ionization chamber are adjusted so as to be overlapped with each other.

Abstract: A radiation monitoring device comprises a radiation monitor and a test unit for testing the radiation monitor. The radiation monitor includes a radiation detector and a measurement unit. The test unit includes a test pulse generator and a test pulse controller. The measurement unit includes a counter circuit, a computing part that computes a count rate with the standard deviation kept constant, an input switching circuit. When a test mode is selected in the radiation monitor, the test pulse controller changes the repetition frequency of test pulses in a step-function manner to the same repetition frequency of a start count rate specified as reference, replaces a count rate in the computing part at current computing cycle with the start count rate, switches the input switching circuit to the test pulse input at next computing cycle to start the test, and then finishes the test after a predetermined time elapses.

Abstract: In order to obtain a radiation measurement system in which a shield is reduced in size to achieve reduction in cost and missing measurement is not present in the whole measurement range, and which is good in stability and responsiveness, a radiation detector which is low in measurement range of radiation is arranged in a sample vessel in which a sample gas serving as a radiation measurement object is made to flow; a radiation detector, which is high in measurement range having a measurement range that follows the radiation detector which is low in measurement range of radiation, is arranged outside the sample vessel; and the sample vessel and a plurality of the radiation detectors are surrounded by a shield to shield from environmental radiation.

Abstract: In order to obtain a radiation measurement system in which a shield is reduced in size to achieve reduction in cost and missing measurement is not present in the whole measurement range, and which is good in stability and responsiveness, a radiation detector which is low in measurement range of radiation is arranged in a sample vessel in which a sample gas serving as a radiation measurement object is made to flow; a radiation detector, which is high in measurement range having a measurement range that follows the radiation detector which is low in measurement range of radiation, is arranged outside the sample vessel; and the sample vessel and a plurality of the radiation detectors are surrounded by a shield to shield from environmental radiation.