Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations
Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations
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DOI：
10.1088/1361-6595/aa8ebb
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发表时间：
2017-10
影响因子：
3.8
通讯作者：
A. Wijaikhum;D. Schröder;S. Schröter;A. Gibson;K. Niemi;J. Friderich;A. Greb;V. Schulz-von der Gathen;D. O’Connell;T. Gans
中科院分区：
文献类型：
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作者：
A. Wijaikhum;D. Schröder;S. Schröter;A. Gibson;K. Niemi;J. Friderich;A. Greb;V. Schulz-von der Gathen;D. O’Connell;T. Gans
低温大气压等离子体射流（APPJs）中活性氧（ROS）的高效生成是一个越来越重要的课题，例如在等离子医学领域对温度敏感的生物样品的处理。研究了一种13.56 MHz射频驱动的APPJ装置，该装置使用氦气和少量氧气混合物（高达1%），在低温下产生均匀的辉光模式等离子体。利用以λ = 255 nm为中心的Hartley波段，利用宽带吸收光谱测量了11 mm宽放电通道上臭氧的绝对密度，臭氧是最突出的活性氧之一。采用双光束装置，参考光束在马赫-曾德配置，以提高信噪比，允许在所研究的单通弱吸光度下进行高灵敏度测量。结果与气体温度测量相关，由引入空气杂质的N2 （c3 Π u +→b3 Π g +, υ = 0→2）光学发射的旋转温度推断。在零维等离子体化学动力学模拟中，分析和解释了观察到的两个量作为射频功率输入和氧混合物的函数的相反趋势。当射频功率变化时，气体温度以及O和O2（b1 Σ g +）的密度影响O3的绝对密度。
The efficient generation of reactive oxygen species (ROS) in cold atmospheric pressure plasma jets (APPJs) is an increasingly important topic, e.g. for the treatment of temperature sensitive biological samples in the field of plasma medicine. A 13.56 MHz radio-frequency (rf) driven APPJ device operated with helium feed gas and small admixtures of oxygen (up to 1%), generating a homogeneous glow-mode plasma at low gas temperatures, was investigated. Absolute densities of ozone, one of the most prominent ROS, were measured across the 11 mm wide discharge channel by means of broadband absorption spectroscopy using the Hartley band centred at λ = 255 nm. A two-beam setup with a reference beam in Mach–Zehnder configuration is employed for improved signal-to-noise ratio allowing high-sensitivity measurements in the investigated single-pass weak-absorbance regime. The results are correlated to gas temperature measurements, deduced from the rotational temperature of the N2 (C 3 Π u + → B 3 Π g + , υ = 0 → 2) optical emission from introduced air impurities. The observed opposing trends of both quantities as a function of rf power input and oxygen admixture are analysed and explained in terms of a zero-dimensional plasma-chemical kinetics simulation. It is found that the gas temperature as well as the densities of O and O2(b 1 Σ g + ) influence the absolute O3 densities when the rf power is varied.