Ionized Molecular Hydrogen Build-Up and Confinement Inside the Space Charge of a Continually Resupplied Electron Cloud
Ionized Molecular Hydrogen Build-Up and Confinement Inside the Space Charge of a Continually Resupplied Electron Cloud
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电离分子氢在持续补给的电子云的空间电荷内的积累和限制
DOI：
10.1109/tps.2021.3138335
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发表时间：
2022
影响因子：
1.5
通讯作者：
Weathers, Duncan L.
中科院分区：
文献类型：
--
作者：
Kiester, Allen S.;Ordonez, Carlos A.;Weathers, Duncan L.
构造了一个圆柱对称的电磁离子陷阱，它产生了一种适合于用持续补充的电子云的空间电荷来限制离子的势。该捕获器使用永久磁体来形成圆柱形几何形状的磁场环形尖端的线性阵列，并且包括对尖端磁场的静电堵塞。离子源是直接在陷阱内的受控热分子氢泄漏的电子轰击电离，而由这些自相同的电子产生的势垒是离子限制的机制。离子陷阱的独特之处在于，限制体积具有相对最小的外部静电场和磁场侵入旨在限制离子的区域，而不是整个轴向磁场。另一个突出的特点是，在陷阱内电子无法接触到的两个位置包含静电元素，这与陷阱中的电子一起提供了轴向离子限制。注入电子时，离子信号在几十个预期的轴向离子传输时间内强度增加，从而证明了离子的积聚，从而证明了离子的限制。对几种固定分子氢分压的电子注入枪的入射电子电流范围进行了研究，并用陷阱的全粒子模拟进行了解释。数据是通过微通道板和荧光屏组件获得的，偏置的方式只能由离开陷阱的正电荷粒子激发。结合模拟的带电粒子总数估计和测量数据，对平均寿命进行了数量级的估计。
A cylindrically symmetric electromagnetic ion trap has been constructed that creates a potential well suitable for confining ions with the space charge of a continually resupplied electron cloud. The trap uses permanent magnets to form a linear array of magnetic field ring cusps in a cylindrical geometry and includes electrostatic plugging of the cusping magnetic fields. The ion source is electron bombardment ionization of a controlled leak of thermal molecular hydrogen directly inside the trap, and a potential well created by those selfsame electrons is the mechanism of ion confinement. The ion trap is unique in that the confinement volume has relatively minimal external static electric and magnetic field intrusion into the regions intended to confine ions and no overall axial magnetic field. Another standout feature is the inclusion of electrostatic elements in two locations inaccessible to electrons inside the trap that provide axial ion confinement in conjunction with electrons in the trap. Build-up of ions, and therefore confinement, was demonstrated via an ion signal that increased in intensity over a period of several dozen expected axial ion transit times while injecting electrons. A study has been conducted for a range of incident electron currents from the electron flood gun for several fixed partial pressures of molecular hydrogen and interpreted using a full particle-in-cell simulation of the trap. Data were acquired via a microchannel plate and phosphor screen assembly biased in a manner that could only be excited by positively charged particles exiting the trap. An order of magnitude estimate for mean lifetime is made using a combination of simulated charged particle population estimates and measured data.