为了实现大气压环境下稳定的辉光放电,设计了一种新型的针-柱电极结构放电装置。采用针尖直径为56.4μm的不锈钢针作为放电阴极,直径为4 m m的紫铜圆柱作为放电阳极,两者通过精密机械结构保持平行。当针-柱之间间距为2 mm、镇流电阻10 MΩ,放电电阻10 MΩ,测试电阻1 kΩ、放电电压-2740 V、大气压环境、室温、无外部通入气流时,针-柱之间实现了稳定的辉光放电。示波器存储的放电波形和数码相机记录的放电图像验证了从电晕放电到辉光放电,再到火花放电的三种放电模式。该针-柱结构易于用M EM S工艺加工制作,可应用于便携式分析仪器中作为离子源使用。
A new needle-to-cylinder electrode structure was designed to realize the stable glow discharge in ambient air .The stainless steel needle tip with diameter 56.4 μm and the copper cylinder with diameter 4mm were chosen as the cathode and the anode respectively ,which were kept parallel by accurate mechanical structure .In the condition that the distance between the nee-dle and the cylinder is 2 mm ,the ballasting resistor is 10 MΩ ,the discharge resistor is 10 MΩ ,the testing resistor is 1 kΩ ,and the discharge voltage is -2 740 V ,without air flow in ambient air and at room temperature ,the stable glow discharge between the needle and the cylinder was realized .Three different discharge modes can be observed :corona discharge ,glow discharge and spark ,which were verified by the discharge waveform stored in the oscilloscope ,and the discharge pictures were recorded by digital camera .The needle-to-cylinder electrode structure is easy to fabricate by the MEMS technology ,which can be used as the ion source of the portable analyzing instruments .