de la Fuente R, de Celis B, del Canto V, Lumbreras J M, de Celis Alonso B, Martín-Martín A, Gutierrez-Villanueva J L
University of León, Escuela de Ingeniería Industrial, León 24071, Spain.
J Environ Radioact. 2008 Oct;99(10):1553-7. doi: 10.1016/j.jenvrad.2007.12.008. Epub 2008 Feb 20.
A new system has been developed for the detection of low radioactivity levels of fission products and actinides using coincidence techniques. The device combines a phoswich detector for alpha/beta/gamma-ray recognition with a fast digital card for electronic pulse analysis. The phoswich can be used in a coincident mode by identifying the composed signal produced by the simultaneous detection of alpha/beta particles and X-rays/gamma particles. The technique of coincidences with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty (NTBT) which established the necessity of monitoring low levels of gaseous fission products produced by underground nuclear explosions. With the device proposed here it is possible to identify the coincidence events and determine the energy and type of coincident particles. The sensitivity of the system has been improved by employing liquid scintillators and a high resolution low energy germanium detector. In this case it is possible to identify simultaneously by alpha/gamma coincidence transuranic nuclides present in environmental samples without necessity of performing radiochemical separation. The minimum detectable activity was estimated to be 0.01 Bq kg(-1) for 0.1 kg of soil and 1000 min counting.
已开发出一种新系统，用于使用符合技术检测裂变产物和锕系元素的低放射性水平。该装置将用于α/β/γ射线识别的磷光体探测器与用于电子脉冲分析的快速数字卡相结合。通过识别同时检测α/β粒子和X射线/γ粒子产生的复合信号，磷光体探测器可用于符合模式。最近提出了使用磷光体探测器的符合技术，以核查《禁止核试验条约》（NTBT），该条约确定了监测地下核爆炸产生的低水平气态裂变产物的必要性。使用此处提出的装置，可以识别符合事件并确定符合粒子的能量和类型。通过采用液体闪烁体和高分辨率低能锗探测器，提高了系统的灵敏度。在这种情况下，无需进行放射化学分离，就可以通过α/γ符合同时识别环境样品中存在的超铀核素。对于0.1千克土壤和1000分钟计数，估计最低可探测活度为0.01 Bq kg(-1)。
