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Atmospheric deposition of ~7Be by rain events, incentral Argentina

机译：大气沉积〜7be雨赛，激烈的阿根廷

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Beryllium-7 is a natural radionuclide that enters into the ecosystems through wet anddry depositions and has numerous environmental applications in terrestrial and aquaticecosystems. Atmospheric wet deposition of ~7Be was measured in central Argentina. Rain trapswere installed (1 m above ground) and individual rain events have been collected. Rain sampleswere filtered and analyzed by gamma spectrometry. The gamma counting was undertaken usinga 40%-efficient p-type coaxial intrinsic high-purity natural germanium crystal built by PrincetonGamma-Tech. The cryostat was made from electroformed high-purity copper using ultralow-background technology. The detector was surrounded by 50 cm of lead bricks to provideshielding against radioactive background. The detector gamma efficiency was determined usinga water solution with known amounts of chemical compounds containing long-lived naturallyoccurring radioisotopes, ~(176)Lu,~(138)Laand ~(40)K.Due to the geometry of the sample and its positionclose to the detector, the efficiency points from the ~(176)Ludecay, had to be corrected for summingeffects. The measured samples were 400 ml in size and were counted curing one day. The ~7Bedetection limit for the present measurements was as low as 0.2 Bq 1~(-1).Thirty two rain eventswere sampled and analyzed (November 2006-May 2007). The measured values show that theevents corresponding to low rainfall (< 20 mm) are characterized by significantly higher activityconcentrations (Bq 1~(-1)).The activity concentration of each individual event varied from 0.8 to3.5 Bq 1~(-1), while precipitations varied between 4 and 70 mm. The integrated activity by event of~7Be was fitted with a model that takes into account the precipitation amount and the elapsed timebetween two rain events. The integrated activities calculated with this model show a goodagreement with experimental values.
机译：Beryllium-7是通过湿Anddry沉积进入生态系统的天然放射性核素，并在陆地和水平体系中具有许多环境应用。在阿根廷中部测量〜7be的大气湿沉积。安装了雨毛带（地面1米）和个人雨季活动。通过伽马光谱法过滤并分析了雨水样本。使用Princetongamma-Tech建造的40％效率的P型同轴固有高纯度天然锗水晶来进行γ计数。低温恒温器使用超级背景技术通过电铸高纯度铜制成。探测器被50厘米的铅砖包围，以获得放射性背景。使用具有已知量的含有长寿命的Naturaloccurring放射性同位素的水溶液测定检测器γ效率，〜（176）Lu，〜（138）Luands〜（40）K.due到样品的几何形状及其定位检测器，〜（176）Ludecay的效率点必须纠正SummingEffects。测量的样品的尺寸为400毫升，一天均计数固化。本测量的〜7封视限制低至0.2 BQ 1〜（-1）。自样和分析的两次雨赛事（2006年11月 - 2007年11月）。测量值表明，对应于低降雨量（<20mm）的所谓特征在于较高的活性浓度（BQ 1〜（-1））。每个单独事件的活动浓度从0.8到3.5 bq 1〜（-1 ），而沉淀在4到70毫米之间变化。通过〜7BE的综合活动配备了一个模型，考虑到降水量和两次雨季事件的经过时间。使用该模型计算的综合活动显示了实验值的真实性。

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