一、实验原理与步骤 超低温冷凝浓缩法则氡(图1)是将水样中的氡气在负压下被载气(空气)携带通过系统到达浸于液氮中的U形玻璃管内。由于液氮的温度为—196℃,氡的冰点为—71℃,故氡气将在此冷凝成固态被滞留下来。为使氡气更充分地冷凝,在长50厘米,内径5毫米的U形玻璃管中装填直径4毫米的钢珠以加大接触面积。 First, the experimental principles and procedures Ultra-low temperature condensate concentration rule radon (Figure 1) is the radon in the water sample under negative pressure by the carrier gas (air) carried through the system to dip in liquid nitrogen in the U-shaped glass tube. Since the temperature of liquid nitrogen is -196 ° C and the freezing point of radon is -71 ° C, radon will condense into solid state here. In order to allow more complete condensation of radon, a 4 mm diameter steel ball was filled in a U-shaped glass tube 50 cm in length and 5 mm in inner diameter to increase the contact area.