²⁰⁶Pb/²³⁸U isotopic ratios were measured from transient signals produced by laser ablation for a short time period (4 shots with 60 kHz repetition rates). To investigate the effect of the dwell time on the measured ratios, the signal intensities of ²⁰⁶Pb and ²³⁸U were obtained with various dwell times (200, 20, 2, 0.2, 0.1, 0.04, and 0.02 ms). The signal intensities of ²⁰⁶Pb and ²³⁸U increase with shortening the dwell time, and the resulting peak signal intensities of ²³⁸U for three zircons (Plešovice, GJ-1, and Nancy 91500) exceeded 10⁶ cps with the shortest dwell time (0.02 ms). This is mainly due to moderation of the signal intensity of ²³⁸U through averaging the intensity data from neighboring time slices, suggesting that the acquired signal intensity profile does not reflect the actual signal intensities. Based on the moderated signal intensity data, correction of the counting loss due to the detector dead time can be erroneous, and this can be well demonstrated by the changes of the measured ²⁰⁶Pb/²³⁸U ratios with different dwell times. With the correction of the counting loss based on the obtained data and a short dwell time (0.02 ms), the resulting ²⁰⁶Pb/²³⁸U ratios for zircon and glass standard materials were in good agreement with the literature within the analytical uncertainties achieved in this study (2–3%). The data obtained here demonstrate clearly that the acquisition with a short dwell time is essential to obtain reliable elemental/isotopic data from transient signals emanating from single-shot laser ablation and introduction of nanoparticles.

中文翻译：

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铀离子同位素分析，采用高分辨力的多收集器ICP-MS（HTR-MC-ICP-MS）从瞬态信号中进行分析

从短时间内激光烧蚀产生的瞬态信号（以60 kHz的重复频率拍摄4次）测得²⁰⁶ Pb / ²³⁸ U同位素比。为了研究停留时间对测量比率的影响，在不同的停留时间（200、20、2、0.2、0.1、0.04和0.02 ms）下获得了²⁰⁶ Pb和²³⁸ U的信号强度。²⁰⁶ Pb和²³⁸ U的信号强度随停留时间的缩短而增加，三个锆石（Plešovice，GJ-1和Nancy 91500）的最终峰值²³⁸ U的信号强度超过10 ⁶ cps，停留时间最短（0.02多发性硬化症）。这主要是由于信号强度的减弱²³⁸ U通过平均来自相邻时间片的强度数据，表明所获取的信号强度轮廓未反映实际信号强度。基于缓和的信号强度数据，由于检测器死区时间引起的计数损失的校正可能是错误的，并且可以通过在不同的停留时间下测得的²⁰⁶ Pb / ²³⁸ U比的变化很好地证明这一点。根据获得的数据和较短的驻留时间（0.02毫秒）对计数损耗进行校正，得到的结果为²⁰⁶ Pb / ²³⁸在本研究获得的分析不确定性范围内（2％至3％），锆石和玻璃标准材料的U比值与文献非常吻合。此处获得的数据清楚地表明，短停留时间的采集对于从单次激光烧蚀和纳米颗粒引入产生的瞬态信号中获得可靠的元素/同位素数据至关重要。