An application of the environmental radiation detector to scientific education

我们开发了阿尔法射线探测器（用于天然放射性活性物质），直到1992年。传感器是P.I.N.光电二极管。这个设备是安全的，因为它通过连接家用插座和干电池来工作。制造这种探测器的成本不到10万日元。电路是简单的，以便高中生可以很容易地理解。通过该探测器，我们测量了从井水（8升，20 C）中蒸发的^< 218>po:6.0MeV和^<214>Po:7.7MeV的子核发射的α射线的能谱，如图1所示。能量分辨率约80keV。在这种情况下，α射线（^<218>Po和^<214>Po）计数率的时间序列分析如图2所示为实线。峰值为120*25（计数/小时）。我们可以在图2中用虚线表示另一个时间序列数据。该曲线来自于在相同条件下使用供水水（8升，20‰）的测量结果。这个例子显示计数率有点低。通过数据采集和分析，我们与四位高中教师就教育实践进行了合作。

We developed the alpha-ray detector (for natural radio active substance) until 1992. The sensor is P.I.N. photo diode. This device is safely to treat, because it works by connecting a domestic outlet and dry batteries. It costs less than 100,000 yen to make the detector. Electric circuit is simple so that senior high school students can understand it easily.By this detector, We measured energy spectrum, which is shown in Fig.1, of alpha-rays emitted from ^<218>Po:6.0MeV and ^<214>Po:7.7MeV of daughter nuclei of ^<222>Rn, which is evaporated from well water(8 liter,20ﾟC). The energy resolution is about 80keV. In this case, the time series analysis of alpha-ray (^<218>Po and ^<214>Po) counting rate is shown in Fig.2 as a solid line. A peak value is 120*25 (counts/hour). We can show another time series data as a dotted line in Fig.2. This curve comes from a measurement by using water from water supply (8 liter, 20ﾟC) on the same condition. This case shows us a little bit of low counting rate.We corporate with four high school teachers about educational practice through the data taking and analysis.