氧气放电等离子体温度测量研究

为了考察电激励氧碘激光器中放电腔内的宏观气体温度,由两片蚌形铜电极和一根长30 cm内径1.65 cm的耐热玻璃管构成放电腔装置,用一台最高功率500 W,频率13.56 MHz的射频装置对压力1 330Pa的纯氧气体进行了介质阻挡放电研究。利用O2(b,ν=0)的P支发射光谱,分别采用波尔兹曼直线作图法和计算机模拟发射光谱法,测量了氧气射频放电等离子体的宏观气体温度。对于低分辨率光谱,利用高斯拟合进行了分峰处理,利用峰面积表征发光强度,通过波尔兹曼作图法得到了宏观气体温度。利用氦氖激光器测得的光谱仪狭缝函数获得了计算1机模拟发射光谱,以最小二乘法作为判据,通过比较计算机模拟发射光谱和实测光谱获得了宏观气体温度。

Study of plasma temperature measurements for oxygen discharge

A radio-frequency discharge setup was constructed by two shell-shaped copper electrodes and a 30 cm long pyrex glass tube (i. d. = 1.65 cm) to examine the gas temperature of oxygen plasma in electric discharge oxygen iodine laser. The discharge was supplied by a 500 watt, 13.56 MHz radio-frequency power. The gas pressure in the discharge cavity was 1 330 Pa. The temperature of oxygen discharge plasma was measured by using the P branch of O2 (b, v = 0) rotational emission spectrum. Two methods were used to deduce the oxygen gas temperature. They are Boltzman plotting method and computer simulating spectrum method, respectively. Gauss fitting method was used to distinguish spectrum peaks for lower resolution spectrum. The spectrum peak area was used to characterize the optical emission intensity. The gas temperature of oxygen discharge plasma was obtained by Boltzmann plotting method. Alternatively, the optical emission spectrum was simulated by computer modeling with spectrometer slit function which was obtained by He-Ne laser. Consequently, the gas temperature of oxygen plasma was obtained by comparing the computer simulating spectrum and the experimentally observed spectrum according to the least square fitting rule. The measurement results with the two methods agree well. It was concluded that the simple optical technique can be used conveniently in the temperature diagnostics of oxygen radio-frequency discharge plasma.