Guguła Szymon, Kozak Krzysztof, Mazur Jadwiga, Grządziel Dominik, Mroczek Mariusz
Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
J Environ Radioact. 2018 Aug;188:87-94. doi: 10.1016/j.jenvrad.2017.09.018. Epub 2017 Oct 8.
In this work a hand-held spectrometer InSpector 1000 with NaI (Tl) 2″ x 2″ detector has been adapted to fast in situ gamma-ray spectroscopy. Two specially designed mounting stands with shielding have been built, allowing conducting measurements in different geometries. Three particular geometries (NW, IS50, IS00) have been chosen for efficiency calibration and further study. The first one (NW) is intended for small environmental samples (volume ca 140 cm) collected on site. IS50 geometry is a typical in situ geometry meant for radioactivity measurements in soil with detector pointed towards the ground. In this geometry the probe is shielded and mounted 50 cm above the soil surface. The new proposed geometry IS00 is designed in the way that the detector is inserted directly into the soil in order to increase the counting efficiency. The methods of efficiency calibration involved using calibration standards (in NW geometry) and the results obtained in previous in situ measurements with InSpector 2000 portable spectrometer with HPGe detector and ISOCS™ Shield Systems, which is routinely used in environmental measurements. NW geometry turned out to be useful for natural radioisotopes concentrations (K-40, U-238 and Th-232), which significantly exceed typical values of those concentrations observed in Poland. Both IS50 and IS00 geometries are applicative for quick (2 h long measurement) evaluation of typical concentrations of K, U and Th in soils. The newly proposed geometry IS00 is superior as it showed lower detection limits and uncertainties as well as its handling was far easier than of IS50. Authors have proven that hand-held spectrometer InSpector 1000, together with mounting stands and shielding, can be successfully used for fast in situ gamma-spectroscopy. Its relatively small weight and good mobility are additional assets. Moreover, detailed procedures for measurements in each geometry have been developed to conduct such analyses properly.
在这项工作中，配备碘化钠（铊）2英寸×2英寸探测器的手持式光谱仪InSpector 1000已被改装用于快速现场伽马射线光谱分析。已制作了两个带有屏蔽装置的特殊设计的安装架，可进行不同几何构型下的测量。为效率校准和进一步研究选择了三种特定的几何构型（NW、IS50、IS00）。第一种（NW）适用于现场采集的小环境样本（体积约140立方厘米）。IS50几何构型是一种典型的现场几何构型，用于在土壤中进行放射性测量，探测器指向地面。在这种几何构型中，探头被屏蔽并安装在土壤表面上方50厘米处。新提出的几何构型IS00的设计方式是将探测器直接插入土壤中，以提高计数效率。效率校准方法包括使用校准标准源（NW几何构型）以及先前使用配备HPGe探测器和ISOCS™屏蔽系统的InSpector 2000便携式光谱仪进行现场测量所获得的结果，该系统常用于环境测量。结果表明，NW几何构型对于天然放射性核素浓度（钾 - 40、铀 - 238和钍 - 232）的测量很有用，这些浓度显著超过在波兰观测到的典型值。IS50和IS00几何构型都适用于快速（2小时长时间测量）评估土壤中钾、铀和钍的典型浓度。新提出的几何构型IS00更具优势，因为它具有更低的探测限和不确定性，并且其操作比IS50容易得多。作者已经证明，手持式光谱仪InSpector 1000连同安装架和屏蔽装置可成功用于快速现场伽马光谱分析。其相对较轻的重量和良好的机动性是额外的优点。此外，还制定了每种几何构型下测量的详细程序，以便正确进行此类分析。
