Abstract: A radiation measurement value (instantaneous measurement value) expressed by a digital value is displayed in a numeral display area of a display unit of a survey meter. A current value marker that moves in a sliding manner in the horizontal direction in accordance with the radiation measurement value is displayed in a marker display area. A history marker is displayed accompanying that current value marker. The history marker is a marker that shows the direction of change (increasing direction, decreasing direction) and extent of change of the measurement value from the past until now, and is displayed on one of one side and the other side, or both, of the current value marker. The length of the history marker shows the amount of change of the measurement value within a fixed time in the past.

Abstract: Preprocessing is conducted on a unipolar pulse output from a photomultiplier tube, to thereby generate a bipolar signal (bipolar pulse). In the bipolar signal, the falling waveform portion (back slope) of the initial peak waveform is steep, and also cuts across the baseline, whereby it is possible to accurately identify the falling point as the zero crossing point. The accuracy of identification of the pulse width “t” can be improved thereby. In addition to the pulse width, further reference may be made to the crest value of the unipolar pulse, the crest value of the bipolar signal, and the like, when determining line type.

Abstract: A survey meter according to the present invention is a portable radiation measurement device. The survey meter comprises a tip portion, an intermediate portion, and a grip portion. A display unit is provided on the top surface of the intermediate portion. The tip portion extends to the intermediate portion with a bent portion therebetween. The tip portion forms an inclined portion. The grip portion has a constricted portion. A radiation detection unit is provided inside the tip portion and is formed by a plurality of sensors arranged in the right-left direction.

Abstract: Preprocessing is conducted on a unipolar pulse output from a photomultiplier tube, to thereby generate a bipolar signal (bipolar pulse). In the bipolar signal, the falling waveform portion (back slope) of the initial peak waveform is steep, and also cuts across the baseline, whereby it is possible to accurately identify the falling point as the zero crossing point. The accuracy of identification of the pulse width “t” can be improved thereby. In addition to the pulse width, further reference may be made to the crest value of the unipolar pulse, the crest value of the bipolar signal, and the like, when determining line type.

Abstract: A first calculation unit calculates a moving average (dose rate) using a relatively long averaging period (T). A second calculation unit calculates an integrated value (dose rate) using a relatively short time constant (?). In a state in which the moving average is displayed, an alarm determination unit identifies a dose abnormality on the basis of the integrated value. Within a measurement start period, a display switching determination unit identifies a constant dose rate state on the basis of the integrated value. A restoration determination unit identifies the restoration of a dose rate on the basis of the integrated value. If a dose rate is displayed using a large degree of smoothing, sudden increases, and the like, in the dose rate can be identified quickly.

Abstract: A survey meter according to the present invention is a portable radiation measurement device. The survey meter comprises a tip portion, an intermediate portion, and a grip portion. A display unit is provided on the top surface of the intermediate portion. The tip portion extends to the intermediate portion with a bent portion therebetween. The tip portion forms an inclined portion. The grip portion has a constricted portion. A radiation detection unit is provided inside the tip portion and is formed by a plurality of sensors arranged in the right-left direction.