Controlled production of atomic oxygen and nitrogen in a pulsed radio-frequency atmospheric-pressure plasma
Controlled production of atomic oxygen and nitrogen in a pulsed radio-frequency atmospheric-pressure plasma
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DOI：
10.1088/1361-6463/aa8da2
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发表时间：
2017-11-15
影响因子：
3.4
通讯作者：
Gans, T.
中科院分区：
文献类型：
--
作者：
Dedrick, J.;Schroter, S.;Gans, T.
射频驱动的大气压等离子体是在环境压力和接近室温下产生反应物质的有效来源。脉冲射频电源输入提供了额外的控制物种生产和气体温度。在这里，我们演示了在脉冲射频（13.56 MHz）大气压等离子体中，通过改变占空比，在0.1%的空气样混合物（N-2/O-2为4:1）中控制高活性原子氧和氮的产生。利用SOLEIL同步加速器上的DESIRS光束线和高分辨率傅立叶变换光谱仪，通过真空紫外吸收光谱测定了原子氧和原子氮的绝对密度。用氮分子发射光谱法测量了中性气体温度。对于固定的施加电压幅度（234 V），在固定的10 kHz脉冲频率下，将脉冲占空比从10%变化到100%，使我们能够分别在(0.18 +/- 0.03)-(3.7 +/- 0.1)× 10(20) m（-3）和(0.2 +/- 0.06)-(4.4 +/- 0.8)× 10(19) m（-3）范围内调节原子氧和氮的密度。随着占空比的增加，相应的中性气体温度升高11k，最高可达（314 +/- 4）K，相对较小。这种通过调节脉冲占空比和时间平均功率实现的额外控制程度，可能对未来的生物医学应用特别感兴趣。
Radio-frequency driven atmospheric pressure plasmas are efficient sources for the production of reactive species at ambient pressure and close to room temperature. Pulsing the radio-frequency power input provides additional control over species production and gas temperature. Here, we demonstrate the controlled production of highly reactive atomic oxygen and nitrogen in a pulsed radio-frequency (13.56 MHz) atmospheric-pressure plasma, operated with a small 0.1% air-like admixture (N-2/O-2 at 4 : 1) through variations in the duty cycle. Absolute densities of atomic oxygen and nitrogen are determined through vacuum-ultraviolet absorption spectroscopy using the DESIRS beamline at the SOLEIL synchrotron coupled with a high resolution Fourier-transform spectrometer. The neutral-gas temperature is measured using nitrogen molecular optical emission spectroscopy. For a fixed applied-voltage amplitude (234 V), varying the pulse duty cycle from 10% to 100% at a fixed 10 kHz pulse frequency enables us to regulate the densities of atomic oxygen and nitrogen over the ranges of (0.18 +/- 0.03)-(3.7 +/- 0.1) x 10(20) m(-3) and (0.2 +/- 0.06)-(4.4 +/- 0.8) x 10(19) m(-3), respectively. The corresponding 11 K increase in the neutral-gas temperature with increased duty cycle, up to a maximum of (314 +/- 4) K, is relatively small. This additional degree of control, achieved through regulation of the pulse duty cycle and time-averaged power, could be of particular interest for prospective biomedical applications.