Doppler splitting and expansion dynamics of laser-produced plasma plume under a high vacuum ambience
Doppler splitting and expansion dynamics of laser-produced plasma plume under a high vacuum ambience
复制标题
DOI：
10.1039/d2ja00177b
复制
发表时间：
2022-08-31
影响因子：
3.4
通讯作者：
Enokida，Youichi
中科院分区：
文献类型：
--
作者：
Kuwahara，Akira;Murakami，Kenta;Enokida，Youichi
到目前为止，还没有研究过高真空环境（<10 - 1 Pa）下激光烧蚀羽流的膨胀行为和光谱特性。对于同位素识别使用共振电离质谱结合激光烧蚀，时间分辨光谱调查的激光产生的等离子体羽是必要的，因为原子运动的方向影响共振电离后，由于多级电子跃迁的光谱特征。利用纳秒脉冲激光器对Al_2O_3靶烧蚀产生的等离子体羽流进行了激光吸收光谱测量。我们的研究主要强调：（i）在高真空（3.0 × 10−4 Pa）下，由于等离子体羽流中接触层和准腔的形成以及原子的横向运动，在羽流前沿通过后出现了多普勒分裂;（ii）在3.0 × 10 − 4 Pa下，由于激光产生的等离子体膨胀，喷射原子的损失达到43%。此外，显示多普勒分裂区的二维轮廓图可用于可视化垂直和横向方向的原子运动，使其成为共振电离质谱同位素分析的有用工具。
The expansion behaviour and spectroscopic characteristics of laser ablation plumes under a high vacuum ambience (<10−1 Pa) have not been investigated to date. For isotope identification using resonance ionisation mass spectrometry combined with laser ablation, a time-resolved spectroscopic investigation of the laser-produced plasma plume is necessary as the direction of atomic motions affects spectral features upon resonance ionisation due to multi-stage electron transitions. In this article, laser absorption spectroscopic measurements were conducted for the ablated plasma plume generated from an Al2O3 target using a nanosecond-pulsed laser. Our study mainly highlights that (i) Doppler splitting appeared after the plume front passed because of the formation of the contact layer and quasi-cavity in the plasma plume and the movement of atoms in the lateral direction at a high vacuum (3.0 × 10−4 Pa), and (ii) the loss of ejected atoms due to the laser-produced plasma expansion amounted to 43% at 3.0 × 10−4 Pa. Moreover, the two-dimensional contour figure that showed the Doppler splitting zone can be used to visualise atomic motions in the vertical and lateral directions, making it a useful tool for isotope analysis by resonance ionisation mass spectrometry.