Cagniant A, Le Petit G, Gross P, Douysset G, Richard-Bressand H, Fontaine J-P
CEA, DAM, DIF, F-91297 Arpajon, France.
CEA, DAM, DIF, F-91297 Arpajon, France.
Appl Radiat Isot. 2014 May;87:48-52. doi: 10.1016/j.apradiso.2013.11.078. Epub 2013 Nov 28.
The ability to quantify isotopic ratios of 135, 133 m, 133 and 131 m radioxenon is essential for the verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT). In order to improve detection limits, CEA has developed a new on-site setup using photon/electron coincidence (Le Petit et al., 2013. J. Radioanal. Nucl. Chem., DOI : 10.1007/s 10697-013-2525-8.). Alternatively, the electron detection cell equipped with large silicon chips (PIPS) can be used with HPGe detector for laboratory analysis purpose. This setup allows the measurement of β/γ coincidences for the detection of (133)Xe and (135)Xe; and K-shell Conversion Electrons (K-CE)/X-ray coincidences for the detection of (131m)Xe, (133m)Xe and (133)Xe as well. Good energy resolution of 11 keV at 130 keV and low energy threshold of 29 keV for the electron detection were obtained. This provides direct discrimination between K-CE from (133)Xe, (133m)Xe and (131m)Xe. Estimation of Minimum Detectable Activity (MDA) for (131m)Xe is in the order of 1mBq over a 4 day measurement. An analysis of an environmental radioxenon sample using this method is shown.
对135、133m、133和131m放射性氙的同位素比率进行量化的能力对于《全面禁止核试验条约》（CTBT）的核查至关重要。为了提高检测限，法国原子能委员会开发了一种新的现场装置，采用光子/电子符合技术（勒佩蒂等人，2013年。《放射分析与核化学杂志》，DOI：10.1007/s 10697-013-2525-8）。另外，配备大型硅芯片（PIPS）的电子检测单元可与高纯锗探测器一起用于实验室分析目的。这种装置允许测量用于检测（133）Xe和（135）Xe的β/γ符合；以及用于检测（131m）Xe、（133m）Xe和（133）Xe的K壳层转换电子（K-CE）/X射线符合。在130keV处获得了11keV的良好能量分辨率，电子检测的低能量阈值为29keV。这提供了对来自（133）Xe、（133m）Xe和（131m）Xe的K-CE的直接区分。在4天的测量中，（131m）Xe的最低可检测活度（MDA）估计约为1mBq。展示了使用这种方法对环境放射性氙样品的分析。
