碳纳米管阴极强流脉冲发射放气特性研究

Outgassing property of carbon nanotube cathode with intense pulsed emission

为了研究碳纳米管(CNT)阴极强流脉冲发射特性,在2MeV直线感应加速器(LIA)注入器平台上开展了阴极放气特性实验.研究结果表明:碳纳米管阴极强流发射时伴随有严重的阴极放气,阴极放气参与形成阴极等离子体.对于特定的几次实验,通过数值积分估算了阴极材料的放气量为0.8—1.12Pa·L,释放的气体分子数目与电子数目之比为254—203,说明阴极等离子体为弱电离等离子体.分析了二极管电压、发射电流密度。

In order to study the properties of the carbon nanotube（CNT） cathode with intense pulsed emission,the outgassing property of cathode is investigated on the 2MeV linear induction accelerator（LIA） injector.Results show that the cathode has a capability of desorbing gases from the CNT cathode under pulsed high voltage.The outgassing plays an important role in the formation of the cathode plasma.The amounts of outgassing for the several experiments are estimated to be 0.08-1.12PaL,the corresponding ratios between outgassing amount and electron number are roughly calculated to be in a range of 254-203atoms/e^- by numerical integral of pressure,showing that the cathode plasma is weakly ionized.The relationship between diode voltage,emission current density, outgassing amount,and the outgassing molecule number per electron are analyzed.