Apfel R E, Lo Y C
Yale University, New Haven, CT 06520.
Health Phys. 1989 Jan;56(1):79-83. doi: 10.1097/00004032-198901000-00007.
The Superheated Drop Detector (SDD) is a new kind of neutron detector based on the same principle as that of the bubble chamber, except the superheated material is in drop form suspended by a gel or polymer as first described by Apfel (U.S. Patent 4,143,274). Previously, we have developed a theoretical model for the prediction of the threshold neutron energy to nucleate bubbles in our superheated materials and a model for the calculation of the energy dependent response function of SDD. The results of the theoretical calculations agree with the experimental measurements reasonably well. We found the measured response curve of one of our SDDs follows the same trend as the ideal ICRP dose equivalent response curve within 40% for neutrons of energy above 100 keV and within a factor of 10 below 100 keV. Therefore, it is possible to make a rem-response Superheated Drop Detector. We have further calibrated our SDD with 252Cf neutron sources (both bare and D2O moderated). The results are in reasonable agreement with our theoretical predictions, which proves that our model is valid not only for monoenergetic neutrons but also for neutrons from a radioactive source. The principles of operation of our detector, which can be used in neutron dosimetry, area monitoring, and neutron spectrometry, are discussed.
过热液滴探测器（SDD）是一种新型中子探测器，其基于与气泡室相同的原理，只是过热材料呈液滴形式，由凝胶或聚合物悬浮，这一形式最早由阿普费尔描述（美国专利4,143,274）。此前，我们已开发出一个理论模型，用于预测在我们的过热材料中使气泡成核的阈值中子能量，以及一个用于计算过热液滴探测器能量相关响应函数的模型。理论计算结果与实验测量结果相当吻合。我们发现，对于能量高于100 keV的中子，我们的一个过热液滴探测器的测量响应曲线与理想的国际辐射防护委员会（ICRP）剂量当量响应曲线趋势相同，在40%以内；对于能量低于100 keV的中子，在10倍的范围内。因此，有可能制造出一种用于剂量当量响应的过热液滴探测器。我们还用252Cf中子源（裸源和D2O慢化源）对我们的过热液滴探测器进行了进一步校准。结果与我们的理论预测合理相符，这证明我们的模型不仅对单能中子有效，而且对来自放射源的中子也有效。我们讨论了可用于中子剂量测定、区域监测和中子能谱分析的探测器的工作原理。
