This work presents a compact ion-pump that utilizes pyroelectricity for ionization of ambient molecules. The pyroelectric ionization is realized by heating a lithium niobate (LiNbO₃) crystal with low voltage resistive heating (10 V drive voltage, 0.5 W Joule heating) to generate a high voltage across the poled surface of the crystal. Pyroelectrically generated electrons from the polarized surface of the crystal are accelerated using an electric field generated by both the crystal and external titanium (Ti) electrodes biased at ±300 V, which results in the ionization of molecules in the chamber. The low collector current in the pA range ensures that the power consumed due to ionization current is lower than the LiNbO₃ heating power. The ionized gas molecules are accelerated toward the Ti collector electrodes where they are implanted owing to large acceleration produced by the collector electrodes. The system is configured as a sputter pump for gettering ions to reduce chamber pressure from the baseline value of 1.4 μTorr with just the external pump to 1.1 μTorr by incorporating the LiNbO₃ pump. The proof-of-concept of the pyroelectric pumping mechanism is demonstrated using a 140 cm³ stainless steel vacuum chamber, with supplementary turbomolecular and diaphragm pumps and demonstrates that a 50 s thermal cycling of the crystal is optimal for the ion-pump. Pumping action was measured with a Pirani gauge and a hot cathode ion gauge. Analytical modeling and experimental results for pumping speed calculations showed a good match during high-pressure pumping.

中文翻译：

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热释铌酸锂电子发射基离子泵

这项工作提出了一个紧凑的离子泵，利用热电使周围的分子离子化。热电离是通过在低压电阻加热（10 V驱动电压，0.5 W焦耳加热）下加热铌酸锂（LiNbO ₃）晶体以在晶体的极化表面上产生高电压来实现的。利用晶体和偏置在±300 V的外部钛（Ti）电极产生的电场，可以加速从晶体极化表面产生的热释电电子，从而导致腔室内的分子电离。pA范围内的低集电极电流可确保因电离电流而消耗的功率低于LiNbO ₃加热功率。由于集电电极产生的大的加速度，离子化的气体分子朝着Ti集电电极加速，并在其中注入。该系统被配置为用于吸杂的离子，以减少腔室压力从1.4基线值的溅射泵 μ乇只与外部泵以1.1  μ通过将铌酸锂乇₃泵。使用140 cm ³演示了热释电机制的概念验证不锈钢真空室，配有涡轮分子泵和隔膜泵，表明离子泵的最佳晶体热循环时间为50 s。用皮拉尼压力计和热阴极离子压力计测量泵送作用。泵速计算的分析模型和实验结果表明，在高压泵期间具有良好的匹配性。