Development of a high sensitivity detector for Radium in water and a study of Rajium removal.

研制了一种高灵敏度水中镭检测器。这个探测器测量氡，氡是镭的衰变产物。氡通过鼓泡法从水中提取到空气中。样品水的体积是700升。一个70升的空气氡检测仪用来检测氡。该探测器对水中镭浓度的灵敏度约为1mBq/m^3。我们用5万吨的超级神冈探测器测量了纯净水的镭浓度。实测值为0.9 (]SY.+-。[) 1 . (stat.) []() 0.1(系统)兆贝可/ m < @D13@ > D1,或者说,SY。+ - 68.4()。[6] [6] [6](ra) 7.7 / cm < @D13@ > D1。这个水平的镭浓度是我们开始这项研究时的目标。我们还研究了水净化系统中使用的元素能够有效地去除镭。这项测量是用神冈水进行的，其中含有超过100倍的镭。结果表明，反渗透膜、超滤膜和活性炭均能有效去除水中的镭。

A high sensitivity detector for Radium in water was developed. This detector measures Radons which are the decay product of Rajium. Radons are extracted from the water into the air by the bubbling method. The volume of the sample water is 700 liters. And a 70-liter Radon detector for air is used to detect Radons. The sensitivity of the detector to the Radium concentration in water is about 1mBq/m^3.We measured the Radium concentration of the pure water in the 50,000 ton Super-Kamiokande detector. The measured value was 0.9 (]SY.+-。[) 0.1 (stat.) (]SY.+-。[) 0.1 (syst.) mBq/m<@D13@>D1, or equivalently, 68.4 (]SY.+-。[) 6.4 (]SY.+-。[) 7.7Ra/cm<@D13@>D1. This level of Radium concentaration was the goal when we started this research.We also studied what elements used in the water purification sustem are capable of removing Radium efficiently. This measurement was carried out using the kamiokande water which contained more than 100 times more Radium. We observed that Radium can be removed efficintly by Reverse-Osmosis membrane, Ultra-filter and activated charcoal.