JP2020139826A5 - - Google Patents

Claims (6)

A target collection unit that collects air containing particulate radioactive material at the measurement point as a detection target, a radiation detector that detects the amount of radiation emitted from the detection target, and a plurality of natural radioactivity contained in the detection target. Based on the calculation results of the natural radiation amount calculation unit that obtains the radiation amount of the substance, the compensation amount database storage unit that holds the compensation amount according to the radiation amount ratio of the plurality of natural radioactive substances as a database, and the natural radiation amount calculation unit. It is provided with a compensation amount determination unit that determines the compensation amount according to the radiation amount ratio in the plurality of natural radioactive substances from the data held in the compensation amount database storage unit, and is detected by the radiation detector with the radiation amount. It is characterized by having a radioactivity concentration calculation unit that obtains the radioactivity concentration of the detection target based on the compensation amount determined by the compensation amount determination unit and the amount of air collected by the target collection unit. Radioactive dust monitor. The natural radiation amount calculation unit obtains the radiation amount for a plurality of Bi-214 and Tl-208 as the natural radioactive material, and the compensation amount database storage unit obtains the radiation amount for the plurality of the natural radioactive material Bi-214. The radioactive dust monitor according to claim 1, wherein a compensation amount corresponding to the radiation amount ratio with Tl-208 is stored as a database. The radiation detector includes a multi-anode photomultiplier tube and a plurality of columnar scintillators corresponding to the light receiving surfaces of each anode in the multi-anode photomultiplier tube, and a crosstalk prevention member is arranged between the scintillators. The radioactive dust according to claim 1 or 2, wherein a signal processing unit for processing a pulse signal is provided for each channel of the multi-anode in the multi-anode photomultiplier tube. monitor. The target collecting unit has a filter paper for collecting air containing the particulate radioactive substance as a detection target, the radiation detector includes a photomultiplier tube and a scintillator, and the scintillator is the same. The radioactive dust monitor according to claim 1 or 2, wherein the filter paper is formed to surround the filter paper from at least three sides. The radioactive dust monitor according to claim 1 or 2, wherein the radiation detector is composed of a semiconductor detector having a circuit element as a semiconductor element. Air containing particulate radioactive material at the measurement point is collected by the target collection unit as a detection target, the radiation amount emitted from the detection target is detected by the radiation detector, and a plurality of natural substances included in the detection target are detected. The radiation amount of the radioactive substance is obtained by the natural radiation amount calculation unit, and the compensation amount according to the radiation amount ratio in the plurality of the natural radiation substances included in the detection target is held as a database and the natural radiation amount calculation is performed. The compensation amount according to the radiation amount ratio in the plurality of natural radioactive substances is determined from the data held as the database by the compensation amount determination unit according to the calculation result by the unit, and the radiation amount detected by the radiation detector is used. A method for measuring a radioactivity concentration, which comprises obtaining the radioactivity concentration of the detection target based on the compensation amount determined by the compensation amount determination unit and the amount of air collected by the target collection unit.